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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY.
EDITORIALS
POTASH FROM THETPACIFIC KELPS. During the spring and early summer of 1911,systematic work was inaugurated to determine the fertilizer resources of the United States. Sources of supply for phosphoric and nitrogenous fertilizers were more or less well known. There was no known source of Dotash salts, however, of any economic importance. It is abviously desirable that such a source should be found and developed, and this fact was accentuated b y the controversies arising between the ‘‘ Kali Syndicate ” and certain American importers which received much notice in the current press and was the occasion of animated diplomatic exchanges between the Governments of the parties t o the controversy. The resources of the United States in possible sources of “potash” therefore received special attention, and various lines of inquiry were actively prosecuted. One of these, so far, has yielded positive results. (For a complete description of this work see Senate Document 190, Sixty-second Congress, 2nd session, entitled “ A Preliminary Report on the Fertilizer Resources of the United States.”) Balch (THIS JOURNAL, I, 777 (1909) has called attention to the giant kelps of the California coast as occurring in enormous quantities and being especially rich in potash salt. Samples of the kelp from Southern California and the salts derived therefrom were submitted to this office by Mr. Balch in September, 1910,and further data were secured from various sources. Early in the summer, three field parties were organized: Prof. George B. Rigg observed and mapped the kelp beds or groves in about a half of Puget Sound; Prof. Frank M. McFarland surveyed the groves from San Francisco Bay to Point Sur; and Captain W. C. Crandall, of the La Jolla Station of the Marine Biological Association of San Diego, surveyed the groves of the main shore and outlying islands from Point Lorna to Point Conception. Officers of the Bureau of Fisheries made still further observations regarding the kelps of Alaska. I n the work this summer something over one hundred square miles of kelp groves were surveyed, and there is reason t o believe that the total area on the Pacific Coast, from Magdalena Bay t o Shumagin Islands, may possibly be 6 or 8 times this. Quite a large number of kelp and rockweeds were found, although generally the larger groves are , approximately “pure stands.” T w o of the kelps are chiefly of importance as sources of potash. I n the northern groves the important kelp is the Nereocystis Iuetkeana and in the southern groves it is the Macrocystis pyrifera. From Point Sur southward this latter occurs in large groves sometimes several square miles in area, and often in very dense masses. Nereocystis grows in almost any depth of water, where there is a rocky bottom and also a strong tideway or otherwise continual movement of the water.
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Macrocystis grows only on exposed coasts where there is much movement of water, and practically always at depths of from 6-10 fathoms. As the carbon dioxide and the oxygen necessary to the metabolism of the plant must be obtained from the dissolved gases in the water a continually renewed mass of water must be available. This fact, probably, accounts for the difficulties encountered in trying t o artificially propagate these algae under labA rocky bottom oratory of aquaria :onditions. is essential for the holdfasts which these plants have in lieu of roots, and to anchor them. Nereocystis is an annual.. The fruiting season is about over by the middle of July, and in order t o maintain the groves this algae should not be cut before that time. Macrocystis, however, is probably r perennial; at least, its life’% more than a calendar year, and if cut early in the summer, it is said t o be able t o regain its luxuriant growth in 40 days or thereabout. At least two cuttings, therefore, should be practicable. Its habit of growth, moreover, the spores forming on fronds well below the surface, tends to provide against its extinction or serious depletion. Nevertheless, it would probably be wise t o maintain a “closed season” for this algae also and not permit more than two cuttings per season, thus insuring a sufficient fruiting to maintain the groves unimpaired. Some form of governmental protection or control of the groves is obviously necessary t o their maintenance and efficiency. The cutting and harvesting of the kelp is a detail of the industry which is in a far from satisfactory shape. Several forms of cutters have been suggested and a few tried. This is, however, a mechanical detail which American ingenuity will unquestionably settle soon now that it has been shown to be worth while. I t probably wil not be practicable to cut the kelp more than I O or 1 2 feet below the surface of the water, and in the case of the Macrocystis at least a greater depth of cutting should not be permitted, in order to insure fruiting and reseeding of the groves. Kelp was originally a term applied t o the ashes of seaweeds and rockweed, but has become, especially in this country, synonymous with the seaweeds or brown floating algae, and on the Pacific Coast is applied popularly to the two plants cited above. These plants among other characteristics have this is common, they absorb relatively large amounts of potassium chloride from the sea water, much larger than most other algae either of the Pacific or other waters. Dr. J. W. Turrentine has made a large number of analyses. From his data it appears that Nereocystis contains about 30 per cent. of its dry weight of potassium chloride and Macrocystis nearly as much. With both kelps, as they dry out, large quantities of potassium chloride, mixed with varying amounts of other salts,
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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
efloresce on the surface, and can be removed readily by simply shaking. Practically all the potassium salts can be obtained b y lixiviation of the dried plant or of its ash. Neither Nereocystis nor Macrocystis of the Pacific littoral contain as much iodine as many other seaweeds and rockweeds. Nevertheless, the amounts present are notable and contrary to popular belief; the southern kelp contains more than does the northern. According to Turrentine’s analyses Nereocystis contains about 0.16 per cent. and Macrocystis about twice as much. Besides iodine, other useful products can be obtained from these kelp, of which, however, space will not permit a discussion here. It is not possible as yet to give an accurate estimate of the amount of potassium chloride which the Pacific kelp groves can yield annually. With all conditions a t their best the maximum possible yield might b.e in the neighborhood of 8 million tons, worth a t present prices about $300,000,000. No such yield is probable, however, a t least in the near future. Taking every cons deration, and leaning strongly t o conservatism i t may be said that it ought to be perfectly practicable to obtain an annual yield of at least a million tons of potassium chloride, worth a t present prices upwards of $30,000,000. The iodine obtainable a t the same time should go far toward paying the expenses of harvesting the kelp and extracting the potash. I t has been assumed in some quarters that because the kelp can be made to yield about three times the present total potash importations from Germany the latter will be stopped or greatly diminished. This is very much to be doubted. Existing business engagements will ensure continued importation for some years to come. I t is possible, and greatly to be desired, that potash from American kelp will reduce the price of potash salts. But the vast bulk of the potash salts goes into the South Atlantic States because these states a t present are the great fertilizer consumers. Inevitably the Trans Mississippi States must soon use fertilizers and in fact the movement has already begun. A very large increase in the consumption of fertilizers, and therefore of potash, may be anticipated within the next few years, enough probably to take up the American production in sight and the importation to be obtained from Germany as well. The great importance of the kelps lies not in the probability of their excluding German potash, but ( I ) if properly managed, in preventing a monopoly and regulating prices; (2) in making possible a greatly extended use of fertilizers, and thereby perhaps even stimulating importations; and (3) in times of stress, giving the country a resource and preventing the agricultural interests from being a t the mercy of an outside power. F. K. C A M E R O N .
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SURFACE COMBUSTION.
In view of the wide-spread publicity given to the lecture of Professor IT. A. Bone, of Leeds, before the American Gas Institute at St. Louis and the Chemsits’ Club in New York, October, and especially in view of the general acceptance by gas engineers and chemists in general of his process as a new discovery in combustion, it seems highly desirable to present a brief review of this art. Professor Bone’s demonstrations were all concerned with the burning of explosive gaseous mixtures continuously by method which (quoting) “consists essentially in injecting, through a suitable orifice at a speed greater than the velocity of back firing, an explosive mixture of gas (or vapor) and air in their combining proportions into a bed of incandescent, granular refractory material, which is disposed around or in proximity to the body to be heated.”
This method of burning explosive gaseous mixtures was used by C. E. Lucke, in 1900, or about eleven years ago. I t was made the subject of a long series of experiments, the results of which were published in a paper entitled “The Heat Engine Problem,’’ presented to the American Society of Mechanical Engineers, December, I 90 I , and forming part of his Doctor’s Dissertation, from which the following is quoted: “The desirability of being able to burn a n explosive mixture continuously and non-explosively under commercial rather than laboratory conditions having been long obvious, a series of experiments was undertaken a t Columbia University with this end in view. Many experiments were made and various results obtained, but as a full account would take too much space and avail little, only a few characteristic experiments will be noted as leading up to the result. Consider a mass of explosive mixture passing through a non-conducting tube with a uniform velocity, v . Then, if inflammation be started at some point, the surface of combustion may remain a t rest or move with or against the current. Denote the rate of propagation by r. Then, when v is greater than r the surface of combustion will move with the current, and if the tube has an end, the flame will ‘blow OB’ and combustion cease; if v = r the surface of combustion will remain a t rest, other influences being inoperative; if v is less than Y , the surface of combustion will move back toward the source, or ‘back flash.”’ “ I n a practicable system of burning an explosive mixture continuously, we may state the following as desiderata and later see how they can be secured. I. ‘Back flashing’ must be prevented. 11. ‘Blow off’ must be prevented. 111. Combustion surface must be localized. IV. It must remain localized for wide ranges of feed or velocity of fl\~wof the mixture. V. The localization must be unaffected by changes of temperature. VI. Large or small quantities must be burned without affecting the above, and the transition from very small quantities to very large, or vice versa, however sudden, should be easy. The first requirement might be accomplished in three ways: ( a ) By using a long tube of some conducting material and so small in diameter as to prevent the passage of the flamecap under any circumstances. ( b ) By using wire gauze*screens.
