May 18, 1883.] 



SCIENCE. 



429 



trading the soluble arseniate witli water, acidulating 

 the solution with nitric acid, boiling to expel carbon 

 dioxide, neutralizing carefully with ammonia (the 

 reaction should be faintly alkaline rather than acid), 

 and precipitating the arsenic in the cold with argen- 

 tic nitrate as the brick-red salt Ag3As04. The 

 latter is thrown on a filter, washed well, dissolved 

 in nitric acid, and the silver determined by titra- 

 tion with ammonium or potassium sulpho-cyanate, 

 whence the arsenic can readily be calculated. The 

 results communicated showed very remarkable con- 

 cordance, and apparently a high degree of accuracy. 

 The exact degree of accuracy does not appear; since 

 the percentage of arsenic in some of the substances 

 tested was not determined gravimetrically, but 

 assumed to be that required by tlieory. By this 

 method, 0.1 gr. of enargite yielded 19.03 and 19.09% 

 arsenic in successive trials. 0.0.5 gr. pure pronstite 

 gave 15.08% arsenic, while 15.15% is theoretically 

 required. An ore mixture gave respectively, 3.26, 

 3.30, 3.19, and 3.25% arsenic in different trials. A 

 copper matte yielded 0.47 and 0.46% arsenic in 

 successive determinations. Antimony, the pres- 

 ence of wliich in solution would vitiate the results 

 of analysis, is almost entirely excluded by the use of 

 sodium carbonate in the fusion. In a mixture of the 

 enargite above tested with stibnite, 19.13% arsenic 

 was found. No experiments were made to test the 

 solvent action of the ammonium nitrate in the 

 solution on the argentic arseniate. The advantages 

 claimed for the method are the great ease and 

 rapidity with which a determination can be made, 

 and the high degree of accuracy attainable, fully 

 suflScient, at least, for technical purposes. — ( Col. sc. 

 soc. ; meeting Feb. 5. ) - [879 



AGRICULTUBB. 



Action of peat on insoluble phosphates. — 



In an extensive series of experiments carried out at 

 the Moor experiment-station in Bremen, Fleischer 

 finds that certain peats exert a very considerable sol- 

 vent action on phosphates. The first experiments 

 were made in the laboratory by intimately mixing 

 finely ground peat and j)hosphate, adding water, and 

 allowing the mixture to stand, usually for three days. 

 Peat from the lowland moors showed no solvent ac- 

 tion ; but that from highland moors (sphagnum peat) 

 acted upon the phosphates in every case but two, 

 dissolving from three or four to over fifty \yer cent 

 of the phosphoric acid present, according to the 

 nature of the phosphatic material. The materials 

 used may be arranged in about the following order, 

 the more soluble first: pure dicalcic phosphate, pre- 

 cipitated tricalcic phosphate, fine raw bone, steamed 

 bone, commercial precipitated phosphates, bone-ash, 

 crude Mejillones guano, Lahn phosphate. The action 

 appears to be due to the presence of free humic acid, 

 which decomposes the phosphates. In several cases 

 the action went so far as to produce free phosphoric 

 acid. Addition of potash-salts was found to increase 

 the solvent action. These results are entirely in 

 harmony with those that have been obtained in field- 

 experiments on these soils. Almost invariably, in- 

 soluble phosphates have given better results than 

 soluble ones, the reason evidently being, that, owing 

 to the small absorptive power of peat, the soluble 

 phosphates are soon washed out of the soil, while the 

 insoluble phosphates yield up their phosphoric acid 

 so slowly that the plants can utilize most or all of it. 

 Experiments were also made in composting phos- 

 phates and peat. Here, also, phosphoric acid was 

 dissolved, but not to so great an extent as in the 

 laboratory experiments, where a much more intimate 



mixture of the materials was possible. From 0.6 to 

 9.2 per cent of the total phosphoric acid was dissolved. 

 Potash salts increased the solubility of the jjhos- 

 phates. A large proportion of the phosphoric acid 

 was rendered soluble in ammonium citrate; that is, 

 brought into a condition similar to that of the so- 

 called reverted phosphoric acid. In connection with 

 these experiments, Kissling has studied the effect of 

 the presence of vailous salts on the action of peat 

 upon phosphates. Potassium sulphate increased the 

 action decidedly, potassium chloride to a less de- 

 gree, and sodium nitrate and kainit hardly at all. 

 Gypsum and calcium chloride decreased the solvent 

 action, and potassium carbonate destroyed it al- 

 together, presumably by neutralizing the humic acid 

 of the peat. The effect of the potassium sulphate 

 was found to be almost exactly in proportion to 

 the quantity used. Although the solvent action of 

 peat, and of peat and potash salts, appears to be com- 

 paratively slight on the large scale, it is not with- 

 out importance ; since, in the soil, it may continue 

 for a long time, and the products of the reaction may 

 be continually removed by the movements of water 

 in the soil and the action of vegetation. Fleischer 

 found, that, after his mixtures of peat and phosphates 

 were washed out, the action apjjeared to begin afresh ; 

 and something very like this must occur in the soil. 

 --{Landw.jahrb.,xu. 129, 193.) h. p. a. [880 



GEOLOGY. 



The Bo-w and Belly River districts, North- 

 West territory. — The rocks of the foot-hills and 

 east of the mountains, according to G-. M. Dawson, 

 are entirely of cretaceous and Laramie age, overlain 

 by bowlder clay and other beds referable to the glacial 

 epoch. The geology of the region is complicated by 

 the fact, tliat, in the immediate vicinity of the moun- 

 tains the beds change considerably in lithological 

 character, the change being such as would be ex- 

 pected to occur on the approach to a shore-line. So 

 far, no reason has been found to suppose that any 

 beds newer than the Laramie (including under this 

 general name the .Judith River and Fort Union series) 

 have been found in this district, or, indeed, in any 

 part of the Canadian North-West territory. The 

 general arrangement of the rocks is given in the fol- 

 lowing table : — 



I. Laramie (including Judith River series). — I. Beds of the 

 Porcupine Hills ; massive sandstones, with shales, etc. 2. Willow 

 Creek beds : reddish and purplish clays, with gray and yellow- 

 ish sandstones. 3. St. Mary River series ; .sandstone shales And 

 clays of general grayish or grayish-green colors. 4. Yellowish 

 sandstones and shaly beds, with a mingling of fresh-water and 

 brackish or marine raoUusks. 



II. Fore Hills. — 1. Yellowish sandstones, with some shales, 

 apparently irregular in thickness and character; moUusks all . 



III. Pierre group. ^1. Blackish and lead-colored shales, with 

 occasional sandstone intercalations, especially toward the moun- 

 tains. 



IV. Niobrara? — Belly River series: sandstones, shales, and 

 sandy clays. Upper part generally grayish; lower, yellowish, 

 and often banded by rapidly alternating beds. Fresh and brack- 

 ish water mollusks. 



Near its base, the Laramie of this region is a per- 

 sistent lignite or coal-bearing formation. In the 

 Pierre group, the most persistent coal-bearing horizon 

 is at its base, although there is a coal-seam at its sum- 

 mit on Bow River. Mr. Dawson considers the coal- 

 bearing horizon at the base of the Pierre to be nearly 

 equivalent to that at the base of the Chico group, 

 which yields the coals of Vancouver Island at Na- 

 naimo and Comox. (In this connection it is well to 

 remember that the identity of the so-called Chico of 

 Vancouver Island with the group of that name in 



