Millions from Waste by Frederick Arthur Ambrose Talbot - HTML preview

CHAPTER VI
 SAVING THE SCRAP FROM THE SEA

If the human race be extravagant in one, more than in any other direction, it is undoubtedly in connection with the utilization of the harvests of the sea. It is a failing as strongly asserted by the primitive as by the cultured races. The aborigine, when there is a big run, will trap as many fish as he can, not for consumption, but apparently for the mere sake of catching his prey. He will select what he requires and leave the remainder to rot. His civilized brother pursues a broadly similar course, only in this event decomposition may not be permitted to run its course without fulfilling a beneficial purpose. The process can be harnessed, as it were, to a more or less useful function.

Improvidence in the consumption of fish is particularly noticeable among those nations which are able to point to an extensive salt-water front, combined with a densely-settled population within a relatively small area. It becomes accentuated when the country is possessed of an intricate and excellent system of rapid inland transportation, allowing the prompt movement of the catches from the points of landing to the centres of consumption.

Such a country is Great Britain. With us fish is an exceedingly cheap food and one which, normally, is readily procurable in adequate quantities. The “long haul” by rail occasions no apprehensions, inasmuch as the railway transport problem, so far as fish is concerned, has been magnificently solved, it being possible to move consignments four hundred, even six hundred miles within a few hours.

The sea’s contribution to the table is prolific. At the same time it is variable. This factor in itself conduces towards pronounced wastage. We seem to have failed lamentably in our efforts to cope with the alternating spells of plenty and relative scarcity in a scientific manner. We have not mastered the adjustment of seasonal gluts, arising from the periodic massed movements of the fish, to shortages in order to maintain a steady and uniform supply the whole year round. In view of the immense strides which have been made in the art of preserving perishable foodstuffs, this deficiency is certainly somewhat remarkable.

The extremely low prices at which the bulk of the food from the sea, particularly of herring and sprat—occasionally mackerel—is available, are primarily responsible for the extravagance which rules. This state of affairs offers another interesting illustration of the fact that extremely cheap living promotes waste. We need only to recall the experience of the war to assure ourselves upon this point. Under the system of price control, coupled with abnormally high rates, fish purchases had to be conducted by the trade with extreme caution to obviate financial losses, while, similarly, the consumer was compelled to be more economic and less fastidious in his, or her, tastes. Under such conditions far less of the single fish was wasted, while greater ingenuity was exercised in the preparation of the less attractive edible portions for the table.

Nevertheless, no matter how extreme the care or economy manifested, a certain degree of wastage is unavoidable. For the most part the offal, which in itself is appreciable in volume, is regarded as irreclaimable and valueless except as a fertilizer. But this reasoning is fallacious. Fish-waste is capable of furnishing raw material in several forms to feed other industries. As yet this notable circumstance has not become fully appreciated in these islands, the practicability of using such refuse only having been established during the past few years.

Ability to turn fish offal to distinct profitable advantage not only solves the problem in its economic aspect, but at the same time indicates a promising outlook for glut catches and to which the ordinary markets are often denied. In this country the conventional disposal of surplus fish is decidedly deplorable for the reason that it follows the line of least resistance. A glut or late catch is generally sold at an absurd price in bulk to serve merely as manure.

If the fish could be turned directly into the soil such a use might not be exposed to severe condemnation, although it is to be deprecated because it represents a serious misuse of valuable food. But, as a rule, this cannot be conducted with the essential promptitude for obvious reasons. Then the farmer suffers a heavy loss. Vigilant gulls and other birds having a well-defined penchant for fish diet raid the land to enjoy a Gargantuan feast with the minimum of effort on their part. The birds will even follow a train, or road wagons, bearing a manurial consignment of their food, for miles from the point of landing and then, after it has been dumped, will swoop down to gorge themselves to the full. In many instances a farmer has been known to lose at least 50 per cent. of his purchase in this manner. He may essay alert and effective measures to combat the birds’ attacks, but he will find it an unequal contest. In one instance, which came before my notice, the insatiable birds, catching sight of one or two open trucks laden with a freshly-landed catch en route to the land, attacked the wagons so vigorously as to cause a very perceptible shrinkage in the load before it reached its destination. Another farmer, who had been persuaded to buy two or three truckloads of freshly-landed fish just because it was cheap, subsequently expressed his doubt as to whether he had driven a good bargain after all. The birds attacked the field over which the loads were distributed in such overwhelming numbers as to prompt the opinion that the field really contained more gulls than fish! So, after all, it is extremely questionable whether the purchase of a bumper catch for use as a fertilizer is really such a bargain as it may appear from a cursory reflection.

In our large cities and towns the treatment of fish offal and surplus supplies drawn from the markets, stores, and retail shops, as well as the hotels, restaurants, and clubs, for industrial exploitation, should present no difficulty whatever. It is an offal apart and a noisome one. Its susceptibility to rapid decomposition and the emission of obnoxious odours during the process demand its prompt removal. It cannot be handled with other refuse owing to its offensiveness. Consequently the system of special collection by vehicles of the closed tank type has become the general practice. In this manner the disconcerting factor pertaining to the utilization of organic waste—effective segregation at the source—is assured.

Although, so far as we are concerned, the record of practical achievements concerning the industrial utilization of fish-waste is slender, owing to the few firms having been persuaded to embrace this phase of trading, it is consoling to learn that we possess what may be described as the leading authorities competent to deal with this issue in all its varying aspects, and to be equipped with the best approved facilities for conducting this work along the latest and most promising lines. There is one firm in particular which has built up a unique reputation in this direction, having been responsible for the design and construction, as well as installation, of the largest fish-waste reclamation plants in operation throughout the world. Some of these equipments are most elaborate in character, and their very dimensions, activity, scale of operations and prosperity, serve to demonstrate, in the most convincing manner, the enormous wealth capable of being won from fish scrap when the task is conducted along the lines advanced by scientific development. The British firm in question, to whose apparatus I have devoted extensive description in a previous chapter, has been responsible for the complete installations forming part and parcel of the huge canneries scattered along the western seaboard of the North American continent.

It somewhat redeems our own short-sightedness and lack of enterprise to know that we have a firm in our midst which has achieved many distinct triumphs in the great issue of waste reclamation. It retains an imposing staff of highly-trained chemists who have become specialists in this privileged province, and they have devoted especial attention to the exploitation of fish-scrap in the anticipation that this may yet develop into a pretentious British industry. The presiding genius of this organization has also associated himself intimately with the problem from the severely scientific side, as well as becoming thoroughly familiarized with the latest methods as practised in Germany, Scandinavia, and other countries in order to reap full advantage from the lessons which they are able to extend in point of equipment and practice. In the opinion of this active-minded and enterprising authority we have nothing to learn from the foreigner either in point of processes, plant, or efficiency. We merely lack the necessary imagination, initiative, and commercial acumen to be able to reap the full financial and trading harvest to be gathered from the exploitation of fish-scrap. While we are apathetic and backward in this connection our Dominions are alert and astute. We need only to turn to the extensive installation recently laid down in Australia—a model of its type—and which was completed by the firm in question, to grasp what can be accomplished in this peculiar field.

It was extremely fortunate for us, as a nation, to be possessed of the knowledge and creative resources of a progressive firm. During the war, when the economic conditions became so tense, the question of the economic disposal of fish-waste to full commercial advantage suddenly assumed an unexpected significance. Specific raw materials were urgently demanded, and it was decided to search sedulously for additional domestic sources of supply. In the conduct of these investigations the potentialities of fish-scrap were forced to the forefront. The enemy was exploiting this field to its absolute limits, so why should we continue to ignore it? Cognizant of the precise possibilities of this industry and the financial attractions which it possessed the head of the firm of which I have written expressed his readiness to extend all assistance in his power. His knowledge of the craft, together with that of what the enemy could and could not do, proved invaluable, and enabled us to place the recovery of the wealth from this waste upon a solid foundation, and in such a manner as to allow of its indefinite expansion in the future.

So far as turning fish-scrap to commercial account has been concerned in these islands the axiom pertaining to the prophet and his own country has not been wholly applicable. The Germans endeavoured to establish an industry upon this raw material among us but signally failed. One or two small plants were laid down along the broad lines in vogue upon the other side of the North Sea, but they fell so far short of expectations or requirements, and were so strikingly inferior to British thought as to fall into disuse. They have long since been broken up.

The Teuton, however, was not solicitous of the welfare of the British nation in exploiting British fish-waste. He was merely prompted to plant himself here because the necessary refuse—raw material from his point of view—was obtainable in such huge quantities and at a low figure. The output was shipped to Germany, where it commanded an attractive price and was in keen demand. The spurned and rejected of Britain became the highly prized of Germany.

Fish-waste falls into two broad classes, which are yet somewhat sharply defined. These are white fish and oily offal respectively, the herring being the best example of the latter category. Consequently, to conduct fish-waste reclamation and exploitation for the by-products upon a sufficiently comprehensive scale in these islands it would be necessary to separate the offal into the two distinctive classifications at the source. However, this would not be such a perplexing problem as it might appear at first sight. Such segregation is imperative for specific technical reasons, while one must also remember that the salt content of the offal varies widely in the two classes of fish.

Scrap of this character can be induced to yield three commercial products as a result of inexpensive treatment. They are respectively meal for poultry and cattle, oil, and fertilizer. A fourth commodity might be included, namely, fish-glue. Hitherto we have been content to draw upon other countries for our supplies of this article, although abundant raw material for its production has always been readily obtainable. But manufacture was doubtless regarded as being extremely speculative for the simple reason that the demand for this article was severely limited. For some reason or other fish-glue, though extensively used by the peoples of other nations, has never been regarded with pronounced favour in British circles although it cannot be excelled as an adhesive. Probably its peculiarly pungent odour has been responsible for our indifferent appreciation of its virtues. One or two small factories were equipped to conduct domestic manufacture, but they were far from being pretentious in their scale of operation.

Fish-glue has attained its greatest vogue in Germany, Scandinavia, Canada, and the United States of America—the last-named more particularly. Yet there is no reason why it should not become equally popular here. All that is required is to enlighten the community concerning its properties, and here is a grand opportunity for propaganda in support of a new industry. There is no secret associated with its production as might possibly be imagined. The quality most essential to secure its widespread appreciation is merely a display of grim energy, push, and go. It is not a case of being called upon to advance the claims of an entirely new product. It is known more or less throughout the country from the circumstance that it is being exploited in varying degree throughout the world. In these circumstances the manufacture of British fish-glue from British fish-waste presents enormous possibilities, capable of illimitable development.

There are signs that we are bestirring ourselves in this direction. Heretofore fish-glue has always been made from the skins of white fish. It has now been suggested that, in this country, the bones might be put to similar account, the gummy content thereof being quite pronounced. Expert opinion favours the contention that such might be carried out to advantage, but there is one supreme difficulty—the adequate supply of the essential bones. They could be drawn from the filleting trade, but the extent of this supply is somewhat problematical. Fish-bones as such have not yet attained the high estate of recognition as a distinct article of commerce. Nevertheless a possible way out of this difficulty has been suggested. It should be quite practicable, when employing the oil extraction process to which I refer later, to sift out the larger bones before submitting the dry residue to the grinding process. In this way it would be possible to secure a ready supply of the necessary raw material for the production of the glue.

It has also been suggested in certain home circles that herring offal might be treated in such a way as to yield fish-glue, but this represents a venture upon untrodden ground. From such a statement it must not be inferred that this residue could not be induced to yield the substance desired, but so far as is known the offal has never been devoted to this purpose. Nevertheless, the suggestion is to be applauded. It is indicative of the new spirit attending the disposal of fish offal and goes to prove that British commercial pioneering is far from being numbered among the lost arts. The mere launch of the inquiry has sufficed to spur the chemist to investigate the problem, and any success achieved in the laboratory in this direction will represent an enormous progressive stride owing to the magnitude of our herring fishery.

At the moment it is the recovery of the oil, meal, and fertilizer which constitutes the primary objectives of the industry. Of the three possible by-products the meal is doubtless the most remunerative. To a certain degree the contemporary concentration of effort upon the conversion of the offal into meal is due to the fact that this constituted the essence of German endeavour in these islands before the war. This meal was in keen demand in Germany, and the bulk thereof was dispatched to that country and Japan. The interruption of this supply to the former, as a result of the outbreak of hostilities, hit the enemy somewhat severely. Not only was he thus deprived of the crude meal prepared in Britain, but he was also denied the opportunity to turn the waste accruing from the consumption in the Fatherland of the heavy imports of British herring which were also summarily cut off. Doubtless Germany cherishes hopes that her industrious sons, who specialized in this distinctive craft, will be permitted to return to the scene of their former labours and to exploit British fish-scrap once again to the advantage of the German nation upon the conclusion of peace. May the wish become no more than father to the thought. We have not failed to profit from the many lessons taught by the war: we have been forced to recognize the many virtues of fish-meal and have made, and still are making, spirited efforts to repair the losses in this line of trading which, from our indifference and lack of imagination, we lost.

To galvanize British effort the fish-meal and fish-manure (guano) manufacturers have joined hands. Propaganda has been waged vigorously by the association, while agricultural societies and colleges have willingly co-operated to spread the gospel of enlightenment. Farmers have been canvassed sedulously, and the value of these by-products for feeding stock and soil have been brought convincingly before them. As a poultry food fish-meal is declared to be unsurpassable, and this circumstance has been driven well home. The result of this onslaught has been to force the farmer, an admittedly difficult individual to convince, into the admission that these products are possessed of far-reaching potentialities, the result being that, to-day, an increasing demand for fish-meal and guano prevails, which has exercised the obvious effect of stimulating the exploitation of fish-scrap to a very pronounced degree.

During the war circumstances militated against the fulfilment of any impressive programme of development along modern lines. Plant and machinery could not be procured owing to the prior claims advanced by other industries. Consequently the problem became resolved rather into the modernization and adaptation of existing plants, many of which suffered from being woefully inefficient. But even in this direction much was achieved which cannot fail to be of distinct value, since it has served to illustrate what can be done in this field to financial profit. Now that trade is returning to the normal we may safely anticipate a striking advance along the whole industrial line in the installation of comprehensive plants coinciding with the very latest expressions of scientific thought, and which will not fail to conduce to the winning of impressively additional wealth from this hitherto sadly-neglected material.

So far as the white fish is concerned the conversion of the offal into meal represents a straightforward operation. It is merely dried under vacuum along the lines already described, a steam-jacketed drier or concentrator being used for the purpose. If the waste be stale or heavily impregnated with salt it cannot be used as food, the product in this instance being bagged for sale as a fertilizer. But the manufacturer, owing to the enhanced profit to be derived from the sale of the product in the feeding-meal form naturally strives to secure this article, and so, if designed for this use, the meal, after issuance from the drier, is passed through a disintegrator and is then graded through a sifting reel.

It is the exploitation of the herring and the sprat, both in the form of offal, glut catches, and condemned consignments, which presents the most attractive future in these islands. When it is remembered that the annual yield of the sea to the fishermen of Britain represents a round 4,000,000,000 herrings, it will be conceded that here must be a Klondyke of waste. Unfortunately, however, the issue is not so straightforward as it would seem to be. An enormous quantity of the catches are set aside for salting and curing to allow of export to foreign markets. In the past Russia and Germany were our largest customers for this foodstuff, their combined purchases running to a round 800,000,000 lb. and exceeding £4,000,000—$20,000,000—in value. When the fish is salted the treatment of the offal presents a rather teasing problem. Its excessive salt content reacts against its conversion into poultry-meal except in very small quantities which are almost too insignificant to demand attention. When a fish-meal carries salt in excess of 5 per cent. it can be used as a constituent of blended or compounded foods, and then only sparingly. Consequently the possible consumption in this field can only be relatively trifling.

By salting the herring the saline content is increased to 20 or even 25 per cent., and the removal of the added salt offers a supreme obstacle. Fortunately it crops up only at certain seasons, but, at these periods, the quantities of offal and scrap to be treated assume imposing dimensions. As may be imagined, from what has been related, salt is the bugbear to the meal manufacturer and he is hard put to it to bring the figure down to one coinciding with trading requirements. What he desires is a simple, inexpensive process whereby the excessive salt may be eliminated without impairing the other virtues of the material in any way. Needless to say the discovery of such a preliminary treatment, meeting with his desires, will be received with unfeigned delight.

The suggestion has been advanced that the extraneous, or added, salt might be removed by subjecting the offal to a washing process. Undoubtedly, in this way, the desired end could be consummated to a certain degree, but, at the same time, there is the danger that the water would not only carry away the salt but would bear with it an appreciable proportion of the valuable nitrogenous matter which it is imperative should be retained. Unfortunately the salt is not completely free; it permeates the fish through and through and is held by the tissues. In view of the difficulty obtaining the manufacturer, as a rule, converts the heavily salted offal into fertilizer, but the enhanced salt content of the manure is regarded with certain misgivings even by the farmer.

This problem assumed its maximum intensity during the war. Huge quantities of barrelled herrings, destined for export to the countries upon the other side of the North Sea, were held up by the authorities, who feared that they might ultimately find their way into enemy countries. As there was no other outlet for this produce, the salted herrings not being regarded with favour here, these prohibited exports were ultimately thrown upon the hands of the meal manufacturers. Such an instance is decidedly abnormal, but as already mentioned the issue arises to a lesser degree under conditions of ordinary trading, and, consequently, demands a certain amount of attention.

The engineering firm specializing in plants for the exploitation of fish-scrap, to which I have alluded, is attacking this problem in its extensive well-equipped laboratories. The chemist favours the theory that the extraneous salt is capable of ready removal. He also realizes that the perfection of a simple and cheap process to this end will probably accomplish a further beneficial purpose. Traces of blood are occasionally encountered in the offal, and their presence tends to discolour the resultant meal. These might possibly be eliminated contemporaneously with the removal of the added salt.

While I have dealt somewhat at length with the artificial salt problem, as it were, it must not be imagined that it constitutes a constant or inseparable feature of the fish-waste by-product recovery industry: far from it. Herring offal, while extremely varied, falls into certain distinctive classes. There is the scrap, or waste, as well as condemned consignments and surplus incidental to the fresh fish trade, which during the recurring periods undoubtedly touches a very high figure. Then there is the kippering and curer offal, the yield of which is much more formidable and easily recoverable from accumulations at central plants where such work is carried out upon a large scale. The kippering refuse, of course, represents that incurred in the process of kippering the herring and, comprising for the most part the gut of the fish, presents a material having little body or substance.

This waste is difficult to treat except along the most modern lines. For this reason, in pre-war days it was exploited only to a limited degree. Yet its accumulation was enormous. At some plants the piles of such refuse, which were to be seen, contained several hundred tons. It failed to arouse earnest attention until the famine in oil burst upon us during hostilities. Then these dumps created interest because it was realized that such residue is rich in oil, enormous quantities of which were lying dormant. Forthwith plants were erected and equipped with the very latest types of machinery, which augurs well for the continuation of this manifestation of industrial enterprise in the future, owing to the great possibilities attending such reclamation.

Curer offal presents the heads and other waste portions as well as a material quantity of broken fish. This refuse has far more body, and so can be more readily treated to allow the valuable by-products to be recovered.

While we undoubtedly lagged behind our competitors in turning fish-scrap to commercial account it must not be imagined that we completely ignored this potential source of wealth. Nevertheless, for the most part, we were content to conduct operations along obsolete, inefficient lines, obtaining a return far below what might have been recorded. Had these plants been of modern design and equipment fish-waste reclamation would have advanced by leaps and bounds during the war period. As new machinery could not be obtained the main task was to adapt the existing plant to satisfy the demands of the authorities, which proved a task of distinct magnitude in itself, because the majority of the installations in operation possessed no striking feature other than that of being extremely wasteful from every point of view, offering, in fact, the most convincing illustrations of How not to do it!

In some works the practice was to cook the offal in steam-jacketed cookers. Now, when kippering offal, for instance, is being treated, the material, owing to lack of body, tends to coagulate at a certain stage in the process, a large volume of oil being liberated. This oil was skimmed and the residue, resembling a stiff mud, was removed to be wrapped in cloths for submission to extreme pressure in hydraulic presses. This action served to express a certain proportion of the oil remaining in the sludge. The compressed cakes were then transferred to a steam-jacketed drier to be reduced to meal.

This process, which has not yet been completely superseded, suffers from being involved and prolonged, although these do not constitute the most adverse features. The greatest objections to it are the retention of an appreciable quantity of oil in the residue, even after subjection to pressure, which accordingly becomes associated with the meal. The last-named being sold for fertilizing purposes, the presence of the oil is objectionable, while the product also suffers from being low in ammonia. Furthermore, while the sludge is being pressed a pronounced volume of watery liquid is driven out to be lost down the drains. Seeing that this liquid carries valuable manurial constituents its loss is greatly to be deplored, and materially lowers the fertilizing—and financial—value of the meal.

A variation of the foregoing process is made in other works, but it only tends towards greater inefficiency and heavier losses. In this case only the oil resulting from treatment of the material in the hydraulic press is recovered! A third system involves the passage of the pressed cakes through a continuous direct fire-heated drier. This method is particularly objectionable, not only from the offensive odours which are thrown off, but because the ammonia content of the waste undergoes serious depreciation, owing to the high temperature employed. In certain instances the herring offal is even charged into the apparatus without any attempt having been made to separate the oil! Such a system, as will readily be recognized, has nothing whatever to recommend it.

It is the observance of such indifferent and unscientific methods as the foregoing which has been responsible for the commercial possibilities of fish-scrap to be belittled. The oil is undoubtedly ignored intentionally because fish oils are generally held to be worthy of inclusion only among the lowest grades of industrial oils. Nevertheless, were a chemist to be attached to such wasteful plants much needed reforms could be promptly introduced, although it is highly probable that the plants would be scrapped instantly at his instigation because of their lamentable inefficiency.

But we need labour no longer in ignorance. Modern science, as represented by chemistry and engineering, is able to offer an equipment capable of extracting the whole of the oil content down to 1 per cent. In other words, 99 per cent. of the oil contained in the raw offal and scrap can be recovered both cheaply and easily. The loss of such a minute fraction as 1 per cent. undoubtedly represents a remarkable chemico-mechanical achievement.

The new process completely coincides with the dictates of contemporary science. The fundamental features are cooking the refuse under vacuum and the ultimate extraction of the oil by the aid of a suitable solvent such as benzine or other equally volatile spirit, or the benzine extraction system may be used from the very beginning, in a single and complete process. I have described this highly ingenious system in a previous chapter together with the system of operation followed. Obviously while the highest efficiency can only be derived from the installation of the complete plant, the processes being interrelated, the designer found it possible to modernize some of the old-fashioned and wasteful equipments to a very striking degree by the introduction of certain features to meet the exigencies of the moment.

A very convincing illustration of what can be achieved in this connection may be related. A firm specializing in the exploitation of herring offal desired to extend its plant, but was baulked in its intentions owing to the various restrictions which were in force. Accordingly it was compelled to consider the situation of how to derive more from the existing facilities without adding to them, at least only to an insignificant degree. At first sight this may seem to have presented a somewhat intricate, if not actually impossible, undertaking. Yet it was effected.

The modified arrangement introduced is decidedly interesting. The offal is cooked in the steam-jacketed cooker, as much as possible of the oil being skimmed from the mixture at the critical stage of coagulation. The sediment, or mud-like residue, is then transferred to an extractor where the remaining oil is recovered. This converts the residue into a still stiffer substance to be finished off in the ordinary steam-jacketed drier, instead of being completely dried in the extractor as originally designed.

This solution has proved to be exceedingly simple and eminently efficient. Although considerable handling is involved the extracting capacity of the plant has been nearly doubled. The advantages to be recorded are:—

(1) Ability to handle very much larger charges of waste when not reducing the material to a dry meal;

(2) Reduction of the raw material to the extent of the oil removed from the cookers;

(3) Reduction of the time required for the oil extraction by approximately 50 per cent.

Consequently, although the adapted, or modified, process entails the employment of extra labour, a result entirely due in this instance to the disposition of the plant in the works, the firm in question is able to obtain the value of the oil which would otherwise be lost, and which more than offsets the cost of the extra labour involved.

As a result of this development a review of the whole problem associated with the recovery of the by-products from fish-scrap was made. Cooking plant is not so expensive as extraction equipment. The question arose as to whether, or not, it would be possible, by the introduction of suitable automatic handling and other labour-saving devices, to obtain highly satisfactory results and efficiency from a combined plant. If this could be done then it would be comparatively easy and inexpensive to bring many of the existing recovery plants up to date to the advantage of the firms concerned. But the factor of capital outlay demands careful consideration, more especially in all matters pertaining to the utilization of waste products, because costs must be forced down to the irreducible minimum to show the necessary return to render them attractive. The result of close investigation of the issue led to the ultimate conclusion that the cost involved in connection with the cookers, extraction plant, and driers, in all probability, would be heavier than that incidental to the laying down of a straightforward extraction plant, pure and simple, to deal with the raw material and to turn it out as a dry product in one operation. One admitted advantage accrues from subjecting the material to preliminary cooking in steam-jacketed cookers. The oil thus obtained is somewhat better in quality than that derived by recourse to the solvent.

The modified or combined process above described enables one distinct end to be achieved. The objectionable and wasteful, as well as expensive pressing plant can be dispensed with. It also enables the ammonia content of the finished meal to be improved very noticeably, as the following analyses of typical meals produced by the respective processes prove somewhat conclusively.

From the foregoing it will be seen that the enhanced yield of phosphates and ammonia fully justifies the additional expenditure incurred in regard to the plant and labour in connection with the extraction process, quite apart from the main duty of the plant. This is to extract all the oil, multiplying the usual yield many times over. Moreover, the quality of the oil-free meal obviously is superior.

With herring offal the extraction process by benzine ensures nothing being removed except the moisture and the oil. None of the liquor with its valuable ammonia is lost. Consequently the whole of the nitrogenous matter is combined with the resultant fertilizing meal.

To indicate the advantage of the benzine extraction process over the old-fashioned method of cooking, pressing, and subsequently drying the pressed cakes the accompanying analyses may prove informative. They refer to herring-mixed meal produced from kippering offal and damaged herring respectively.

BENZINE EXTRACTION PROCESS.

OLD PROCESS.

Both essential fertilizing constituents are lower by the second than by the first process. This is not surprising in view of the fact that the subjection of the sludge to pressure drives off the watery liquor which is allowed to escape into the drains, notwithstanding that it carries a pronounced proportion of the ammonia and phosphate. Then it will be seen that the benzine process yields a manure carrying a less proportion of the oil which the farmer regards with misgiving, because the oil has been recovered for sale as such. In other words it will be seen that, under the old process, 14.4 per cent. of oil is allowed to pass to the land where it is not required, instead of to industry where it is in keen request. At the prices which prevailed during the war this represented a wastage of £7—$35—per ton of fertilizer.

Under the extraction or solvent process the meal is turned out in a perfectly dry condition, either for use as a poultry food or fertilizer, the recovery of the oil and drying being completed in the one operation. The method is not only the acme of simplicity but it assures the maximum yield of oil, only 1 per cent. being lost. It is also rapid, it being possible to treat a charge of 8 tons of offal in 10 to 12 hours in one unit.

White fish and general offal do not contain sufficient oil to warrant the expense of solvent extraction. If it should be desired to secure 99 per cent. of the slight proportion the offal carries then submission to the benzine process is imperative, for the simple reason that it cannot possibly be recovered in any other way. The modern system of drying such offal is by steam heat under vacuum or reduced pressure.

This process, to which I have also devoted adequate attention previously, not only enables a product of high quality to be obtained, enabling it to command an enhanced price in the market, but it also conduces towards the retention of the nitrogenous contents of the meal. From the fertilizing point of view this is the main end to be achieved. Colour of the meal is another factor which demands recognition. It plays a far more prominent part in the commercial value of the product than might possibly be conceived. The American drying system, operating along direct fire-heated lines, while efficient so far as it goes, namely, the elimination of the moisture, yields a darker coloured meal, owing to the high temperature which has to be used, while, of course, the nitrogen content is lowered by such practice.

The vacuum system has also proved highly efficient for the production of cod-liver oil. The temperature of rendering being low gives an oil of superior colour and odour, two factors of vital importance when the oil is being extracted for medicinal purposes. This is a somewhat delicate product to manufacture, especially when the livers are in a state of partial decomposition, because in this instance colour and sweet taste are particularly vital and difficult to assure.

I have referred to the circumstance that fish oils commercially rule low in the scale of industrial oils. But even fish oils possess one feature common to the highest grades of oils. They carry a certain proportion of glycerine. During the war the oil extracted from fish-scrap and offal was subjected to further treatment to swell our domestic supplies of this indispensable commodity. Even under normal conditions the reclamation of oil from fish waste to secure this glycerine offers further inducement to this phase of industry, and is also capable of considerable development.

Fish oils are also destined to play a more prominent part upon the table than has been the case heretofore. Their inherent fluidity and refusal to solidify, except at low temperatures, have hitherto reacted against their use in this direction. But the increasing demand for margarine as a substitute for butter, and the discovery of the hydrogenating process for eliminating the two outstanding defects, have invested the future for fish oils with additional significance, more especially as by the hardening process, as it is called, the pungent taste and aroma so distinctively of the sea and its inhabitants are removed. By virtue of this discovery fish oils are entering more and more extensively into the manufacture of margarine. The circumstance that they yield a product so closely allied to the genuine article from the dairy as to be difficult of detection, except by elaborate investigation and specialized methods, has served to accentuate this tendency.

We must derive far-reaching benefits from the utilization of our fish waste of every description—not only the offal arising from the preparation of the foodstuff for the table either in a fresh, kippered, cured, or canned condition, but the inedible contributions from the trawls. Those members of the sea’s vast and varied population, such as the whale, which are trapped for certain highly-prized portions of their bodies, must be fully exploited. For decades the whale fishery has been conducted along the most wickedly wasteful lines for which we are paying to-day. The Scandinavian whalers have been among the worst offenders in this respect, but they are now being compelled to turn from the folly of their ways and are endeavouring to utilize the whole of the carcases of their prizes.

So far as the average member of the community in these islands is concerned it is a moot point whether he, or she, has any tangible idea of the magnitude of the British sea-fishing industry. From the abundance and cheapness of the food a vague notion obtains that it must certainly be somewhat impressive. To obtain a graphic idea of its enormous proportions we must venture beyond the limits of domestic consumption and see how we help to feed the foreigner. Under normal conditions we ship approximately 1,250,000,000 lb. of fish every year, representing in value a round £7,750,000—$38,750,000. Of this huge total the humble herring represents nearly 1,120,000,000 lb., valued at approximately £6,000,000—$30,000,000. Of the total herring catch about one thousand million—1,000,000,000—lb. are subjected to curing or salting for the foreign markets, the value of those exports being £5,350,000—$26,750,000—so that the herring may truly be said to form the backbone of the British sea-fisheries. In these circumstances, and bearing in mind the huge quantities handled, the item of waste must necessarily loom heavy. It cannot be avoided. Therefore it behoves us to turn our harvest from the sea to the utmost advantage and to eliminate the item “loss” from our operations.

As the by-products from fish-waste become appreciated we may even proceed to the lengths pursued along the northern Atlantic seaboard of the United States. There the harvest of the menhaden, a fish totally unfit for human consumption, is carried out expressly for the oil obtainable therefrom. It has become a flourishing trade—one which is steadily expanding—special vessels being engaged in the fishery. While it is questionable if much fish of a comparative character and totally unsuited to the table is to be caught in the waters around our coasts, Farther Britain can point to a different state of things. Our Dominions should find it profitable to emulate the American example and exploit adjacent waters essentially for inedible fish to extract the oil and to convert the residue either into fertilizer or poultry food. There is a lucrative and developing market for all three commodities.

But the problem of to-day, in so far as it particularly affects Great Britain, is to solve the issue incidental to the glut catches, so as to prevent the wasteful distribution of the raw fish over the land as the easiest way out of a perplexing dilemma. If we can divert such unwanted hauls from the sea to reclamation factories, confident in the knowledge that there they will be worked up to their utmost in the interests of commerce, we shall be able to record an industrial and economic achievement of incalculable consequence to ourselves. To dump newly-caught fish upon the land merely because it cannot be absorbed by the community as a foodstuff constitutes one of the most deplorably wasteful, if not actually criminally extravagant, charges ever levelled against contemporary civilization.