12 EXPERIMENT STATION RECORD. [Vol. 43 



The gold numbers of protalbinic and lysalbinic acids, R. A. Gortnek 

 (Jour. Aiucr. Clicm., Soc, J,2 {l'J20), No. 3, pp. Jlf^-T-JS?).— Determinations are 

 reported I'roin the Minnesota Experiment Station of tlie gold nnmbers of 

 In-oliill)inic and lysalbinic acids and also of various other colloidal substances 

 with the following results: Dextrin, 125 to 150; soluble starch, 10 to 15; sodium 

 oleate, 2 to 4; egg albumin, 0.08 to 0.1; gum arable, 0.1 to 0.125; protalbinic 

 acid, 0.15 to 0.2 ; lysalbinic acid, 0.1 to 0.125 ; and gelatin, 0.005 to 0.0125. 



Since the results in the cases of gelatin, egg albumin, and gum arable are in 

 close agreement with those of other workers the values are thought to be 

 reliable, and to indicate that the protective action of protalbinic and lysalbinic 

 acids as measured by the gold number has been much overrated. 



Potassium chlorate as a standardizing substance for solutions of alkali, 

 H. ]{. Van Valkenhukgh {.lour. Ainer. Chcni. Sac, J,2 {1920), No. 4, pp. 757- 

 jdO). — A method of standardizing soluti(ms of alkali is proposed which depends 

 upon the reduction of potassium chlorate with sulphur dioxid and the standard- 

 ization of the alkali with the amount of sulphuric acid thus formed as repre- 

 sented by the equation 3S02+KC103+3aO=3H2S04+KCl. 



It is stated that the best results are obtained by purifying the C. P. potassium 

 chlorate by reci-ystallization, drying it from 4 to 6 hours at 240° C, boiling the 

 solution in an open Erlenmeyer flask, and passing sulphur dioxid into the 

 boiling solution for 30 minutes. Care should be taken to remove the excess of 

 sulphur dioxid by boiling, after which the titration is conducted either in the 

 hot or cold, using phenolphthalein as indicator. 



Comparative results of the standardization of a solution of sodium liydroxid 

 against potassium chlorate and against standard acid are reported. With the 

 new method uniform results were obtained which agreed closely with those ob- 

 tained with the standard acid. 



Chemical changes in the composition of saccharin-bicarbonate tablets, 

 O. Beyer {Che»i. Ztg., 43 {1919), No. 132, pp. 751, 752).— Analyses of saccharin 

 tablets after having been stored for different lengths of time showed a progres- 

 sive loss of CO- and of free saccharin. It is thought that sodium saccharinate is 

 formed even in the manufacture of the tablets, and that this increases rapidly 

 on standing. These changes deci'ease the solubility of the tablets. 



Apparatus for the determination of melting points, L. M. Dennis {Jour. 

 Indus, and Engin. ClwnK, 12 (1920), No. 4, pp. 366-368, figs. 2).— Descriptions 

 and illustrations are given of two tubes of slightly different design to be used 

 as the sulphuric acid containers in melting point determinations. The tubes 

 are so constructed that when filled with sulphuric acid and heated the acid 

 circulates through the tube and is maintained at constant temperature, thus 

 avoitling the errors in melting point determinations due to uneven heating of 

 the acid. 



Acidity and acidimetry of soils. — I, Studies of the Hopkins and Pettit 

 method for determining soil acidity, H. G. Knight (Jour. Indus, and Engin. 

 Cheni., 12 (1920), No. 4, pp. 340-344, figs. ^).— The discussions and criticisms in 

 the literature of the Hopkins and Pettit method for determining soil acidity 

 are reviewed, and laboratory studies of various points brought up in these 

 discussions are reported from which the following conclusions are drawn: 



" When normal solutions of potassium nitrate, potassium chlorid, sodium 

 nitrate, stxiium chlorid, and calcium chlorid were liercolated through an acid 

 soil all gave the same end titrations, using phenolphthalein as an indicator. 

 This corroborates Hopkins' statements. 



" The acidity of the salt extract of an acid soil is independent of the tempera- 

 ture witliiu the range from 25° to 90° C. 



