504 EXPERIMENT STATION RECORD. 



same. Appreciable amounts of this substance were noted in normal Swiss and 

 Emmental cheese, esi^ecially in the latter. See also previous notes (E. S. R., 

 14, p. 1115; 21, p. 478). 



An organism similar to those belonging to the Bacillus casci group was 

 isolated from Swiss cheese. The indications were that oxyphenyl lactic acid, 

 was present in both cheeses but no tyrosol could be noted. 



The gravimetric determination of calcium as calcium oxalate, S. Gov 

 {Chcm. Zig., 37 (1913), No. 131, pp. 1337, 1338).— For the determination of cal- 

 cium in foods, soils, plant ashes, etc., the methods in vogue are tedious and 

 time-consuming. In most cases the calcium is determined as oxid or carbonate. 

 Attempts to weigh the calcium oxalate precipitate directly after drying re- 

 sulted in showing the feasibility of the procedure providing the drying was 

 done in the Gooch crucible. The precipitate when dried at from 100 to 105° C. 

 was found to contain one molecule of water of crystallization which will not 

 volatilize by continued drying at the above-named temperatures. By drying at 

 130°, the temperature used in the perchlorate method, a loss in weight is ex- 

 perienced and the salt goes over into the anhydrous condition. 



Study of methods used in alkali determinations, A. E. Vinson and C. N. 

 Catlin {Arizona Sta. Rpt. 1913, pp. 27.'f-277). — This is a comparative study of 

 the methods for alkali determinations in soil, which was prompted by the fact 

 that some investigators were reporting results for black alkali far in excess 

 of the limit usually acceptable as that of tolerance by most economic crops in 

 the presence of very large amounts of gypsum, a result which could not be 

 obtained by methods in use at other station.s. 



The soils used in comparing the methods were a strongly black alkaline 

 soil from the University of Arizona farm, a moderately black alkaline soil 

 from Santa Cruz Valley, and a gypsum soil from Santa Cruz Valley, and the 

 methods studied were the California, Montana, Bureau of Soils, Texas, New 

 Mexico, Utah, and Arizona. The determinations made were total solids, 

 chlorids as sodium chlorid, and alkalinity expressed in terms of sodium car- 

 bonate. The comparisons show that the Arizona method gives high results 

 in all determinations except the chlorids. This is especially true for black 

 alkali, and it was found that it requires a fairly large propoition of water to 

 soil and long digestion to reach a maximum exti'action of total solids. Direct 

 titration of the soil filtrate with methyl orange as the indicator may show 

 black alkali in a strongly gypsum soil and the percentage would increase with 

 the carbon dioxid in the water used in making the solution. 



Colorimetric estimation of iron in water, F. Gothe (Ztschr. Unicrsuch. 

 Nahr. u. Gemissmtl., 27 {1914), No. 9, pp. 676-683; -ahs. in Jour. CJiem. Soc. 

 [London], 1G6 {191J,), No. 621, II, pp. 581, 582).— It is claimed that the colori- 

 metric method of determining iron by means of potassium thiocyanate is liable 

 to yield low results when ferrous salts are present in a water in which the 

 iron has been insufficiently oxidized by treatment with hydrochloric acid and 

 potassium chlorate. The error is due to the influence of the hydrochloric acid 

 on the ferric thiocyanate and to a certain extent on the quantity of thiocyanate 

 added. More satisfactory results can be obtained by oxidation with nitric acid. 



The following procedure is recommended : " One hundred cc. of the water 

 is acidified with 1 cc.'of hydrochloric acid (specific gravity 1.125). a few crystals 

 of potassium chlorate are added, and the mixture is evaporated to dryness. 

 The residue is treated with 1 cc. of hydrochloric acid (specific gravity 1.125) 

 dissolved in distilled water, diluted to 95 cc, and 5 cc. of 10 per cent potassium 

 thiocyanate added. The coloration is compared with that produced by a known 

 quantity of iron under similar conditions." 



