806 EXPERIMENT STATION RECORD. 



A study in the determination of calcium, G. Heise {Proc. loica Acad. Set., 

 17 (1910), pp. 135-138). — This work bad for its purpose the simplification of 

 the gravimetric determination of calcium. The author points out that the 

 precipitation of calcium as oxalate and its subsequent conversion into oxid 

 by heating presents many difficulties and liability to inaccuracies to the inex- 

 perienced analyst. Tests were therefore conducted in order to determine if 

 calcium could be estimated by weighing it directly as calcium oxalate. 



The author concludes as follows: " Calcium can be determined and accurately 

 weighed as the oxalate. It can be very conveniently converted into the car- 

 bonate and weighed as such. The determinations can be carried out in porce- 

 lain crucibles without appreciable error. Either of the above mentioned 

 methods is fully as accurate as the determination of calcium as the oxid and 

 is much more convenient and rapid. Of the 2 methods, the determination 

 as carbonate is somewhat superior to the determination as oxalate, because 

 of the hydroscopic nature of the latter substance." 



Methods of determining the dry-matter content of roots, R. K. Kristensen 

 (Tklsslcr. Landhr. Planteavl, 18 (1911), No. 1, pp. 96-108, figs. 5).— Comparative 

 results obtained with a disc beet sampler and a Helweg " beet saw " showed 

 that the latter gave the more satisfactory and correct results. 



In order to ascertain the degree of accuracy that can be reached in determin- 

 ing the dry-matter content of roots, 60 samples of mangels were taken from the 

 same lot of roots, triplicate determinations being made in all cases. The dry- 

 matter content was found to vary between 13.67 and 15.59 per cent, with an 

 average of 14.60 per cent. The largest deviation from this percentage was 0.99 

 per cent. The average analytical error was 0.36 per cent. As a rule, the error 

 in an ordinary, well-conducted, analysis will not exceed 0.3 per cent, and in 

 most cases is below 0.2 per cent of dry matter. 



Estimation of the doughing value of flour, A. A. Besson (Chem. Ztg., 35 

 (1911), No. 28, jyp. 2J,5, 2.',6; aU. in Analyst, 36 (1911), No. 422, p. 216).— The 

 author found that of the 2 methods proposed by Arragon, that by adding water 

 to a definite amount of flour was the best. He endeavored to standardize the 

 method and to eliminate the sources of error, if possible. It was found that 

 a high result is obtained if all the water is added to the flour at one time, but 

 that when added gradually the results were low. 



The author, therefore, recommends adding at once 50 per cent of water to 150 

 or 200 gm. of the flour in a porcelain dish. The dough is then made as stiff 

 as possible by working it with a glass rod. Strong kneading with the palm of 

 the hand is absoultely necessary, and during the process the dough is squeezed 

 between the fingers and pressed tightly against the palm. More water is then 

 introduced during the process to obtain a uniformly wetted dough. The dough- 

 iug is complete when it no longer sticks to the fingers, and the dough is then 

 scraped together with the spatula and weighed. 



These tests should agree within 1 per cent of added water, but allowance must 

 be made for the moisture originally present in the flour, and the results re- 

 ported in terms of dry substance. 



A new method for the quantitative estimation of saccharose in the pres- 

 ence of other sugars, A. Jolles (Ztschr. Untersuch. Nahr. u. Genussmtl., 20 

 (1910), No. 10, pp. 631-638) .—This method has been previously described (E. S. 

 R., 24, p. 704), and comments thereon noted (E. S. R., 25, p. 412). 



Contribution to the examination of molasses, A. Jolles (Osterr. Ungar. 

 Ztschr. Ziickeriiuhis. ii. Landw., 39 (1910), No. 5, pp. 698-703) .—The author has 

 modified a method previously noted (E. S. R., 24, p. 704) in order to apply it to 

 the analysis of molasses. The results for sucrose, raffinose, and invert sugar 

 obtained with the method were satisfactory. 



