614 EXPERIMENT STATION EECORD. 



smallest possible quantity of hydrochloric acid, and made np to 100, 200, or 500 

 CO., according to the amount of iron present, and the rest of the determination 

 carried out as already described. It has also been obsei*ved as regards the 

 preservation of the stock solution of iron that if instead of making the solution 

 of tlie salt up to bulk with water, a 50 to 60 per cent solution of sucrose 

 (refined sugar) be used, the titer will keep constant almost indefinitely. On 

 making a series of comparative experiments with the sulphid, the thiocyanate, 

 and the ferrocyanid methods, the authors find that the limit of accuracy, 

 expressed in pai-ts of iron per 100,000, is as follows: Sulphid, 0.05; thiocyanate, 

 0.1 ; and ferrocyanid, 0.25, and it was also noticeable that the maximum inten- 

 sity of color is more rapidly I'eached in the sulphid method than in either of 

 the other two. A number of determinations of the iron content by the sulphid 

 method, using siinips (thick-juices), refinery heavy liquors, cane and beet 

 sugiTrs, and molasses, are recorded, and it is shown that except in the case of 

 molasses and low-grade sugars, the result obtained by working with a solution 

 of the product is identical with that found by operating upon the solution of 

 the ash." 



Precipitate produced by mercuric acetate from molasses; isolation of 

 adenin, Stoltzenbeeg {Ztschr. Ver. Deut. Zuclcerindus., 1912, No. 674, PP- 318- 

 S22; abs. in Jour. Chem. Soc. [London], 102 {1912), No. 595, I, p. 397).— Alter 

 clarifying molas.ses with lead acetate, the precipitate produced later by adding 

 mercuric acetate was not found to contain any substances which have a high 

 rotation in a neutral solution. Levorotatory substances were not noted, but 

 when the precipitate was dissolved in hydrochloric acid, dextrorotatory bodies 

 were detected. The mercuric acetate precipitate contains at least two acids 

 and bases but no aspartic acid. The chief product noted was adenin. 



The grinding of spruce for mechanical pulp, J. H. Thickens {U. 8. Dept. 

 Agr., Forest Serv. Bill. 127, pp. 54, pl-'^- 7, flgs. 19). — Experiments at Wausaw, 

 Wis., in cooperation with the American Pulp and Paper Association and the 

 University of Wisconsin, are reported with spruce, as a standard wood, for 

 the purpose of studying the influence which the variable factors such as (1) 

 power applied to the grinder, (2) amount of pulp produced in 24 hours, (3) 

 power consumption per ton of pulp in 24 hours, and (4) yield of pulp and 

 screenings per cord of wood gi-ound, have on the quality and production of the 

 pulp. The following general conclusions are drawn : 



"(1) The power to grinder increases with speed and pressure of grinding and 

 decreases with the degree of sharpness of stone. There is also a very slight 

 Increase in the power required with increase of temperature, other conditions 

 remaining const;int, while the thickness of stock in the gn'inder pit has almost 

 no influence. With all other conditions similar the power to the grinder is less 

 for steamed wood than for gi-een or seasoned wood untreated. 



"(2) The rate of production varies directly with pressure, speed, and degree 

 of sharpness of the stone. Less pulp is obtained in 24 hours vdth seasoned 

 wood than with green, and still less with steamed wood, all other conditions 

 being the same. The temperature and thickness of stock in the grinder pit 

 have little influence on the rate of production. Slightly less pulp is produced 

 at low temperatures. 



"(3) The horsepower consumption per ton, when untreated wood is ground, 

 increases as the pressure decreases, according to a fairly definite law. It is 

 lower on sharp stones than on dull ones and increases as the speed decreases. 

 There is. however, not as much difference between the power consumption per 

 ton at low speed and high speed as there is between power consumption at low 

 pressure and high pressure. The power consumption is very title influenced 

 by temperature, but it is slightly lower at high temperature. The power con- 



