Makch 18, 19-04.] 



SCIENCE. 



443 



to offer a satisfactory way for its deter- 

 mination. The quantity of optically ac- 

 tive substances in wheat flour, as sucrose, 

 invert sugar and the non-giiadin proteids 

 soluble in alcohol, was found to be small, 

 and if desired corrections could be made 

 for these substances by precipitating the 

 gliadin and polarizing the filtrate, the 

 gliadin could be determined by difference. 

 It was found that if 15.97 grams of flour 

 were treated with 100 c.c. of 70 per cent. 

 alcohol for 18 hours with occasional agi- 

 tation, and the filtrate then polarized in a 

 220 mm. tube, the readings on the sugar 

 scale ranged from —4 to —7 according 

 to the amount of gliadin in the sample. 

 It was also found that the polariscope read- 

 ings multiplied by .2 gave results corre- 

 sponding with the per cent, of gliadin 

 nitrogen obtained by the usual process. 

 When the results are siibstituted in the 

 formtila {a)D= — a/ PL, the value ob- 

 tained for the specific rotation of gliadin 

 was found to be —90. Kjeldahl and Os- 

 borne obtained approximately — 92. While 

 only tentative standards could be formu- 

 lated, on account of lack of sufficient data, 

 it woiild appear from the results, obtained 

 that the polariscope offers a rapid and ac- 

 curate method for the determination of 

 gliadin in wheat. 



Factors of Availability of Potash and Phos- 

 phoric Acid in Soils: G. S. Fraps. 

 In the determination of plant food in 

 soils, chemists have usually considered 

 only that part which is soluble in the com- 

 mon solvents. Solubility is not, however, 

 the only factor of fertility in the soil. 

 The rate of decomposition or weathering 

 of the soil is of great importance, as is also 

 the power of the plants to assimilate. 

 Weathering has received little or no at- 

 tention. It is known to be of great im- 

 portance with nitrogenous bodies, but in 

 regard to phosphorus and potash no data 



can be given. Experiments show that 

 there is a slight increase in both phosphoric 

 acid and potash when the soil is kept moist 

 and a great increase in potash when or- 

 ganic matter is present. This accounts for 

 the necessity of vegetable matter in soils. 

 Another factor is the difference in the 

 solvent powers of plants. A soil may con- 

 tain sufiicient food for one plant, but not 

 enough for another. 



Thirty Years' Progress in Water Analysis: 

 Ellen H. Eichaeds, Massachusetts In- 

 stitute of Technology, Boston, Mass. 

 It is hardly possible- for the younger 

 chemists to appreciate the benighted con- 

 ditions in which the early '70 's found us. 

 Wanklyn's book, written in 1868, was the 

 first book published on the subject of water 

 analysis alone. Frankland and Arm- 

 strong, between 1866 and 1888, made 

 critical examinations of methods, and 

 reached important conclusions as to the 

 meaning of the presence of the various 

 substances in drinking-water. 



During this time occurred a bitter con- 

 troversy over the question whether the 

 whole of the organic carbon and nitrogen 

 or only a certain ratio of the total was im- 

 portant. It must be remembered that at 

 this time chemistry was still young in this 

 country. There were a few laboratories 

 in the better scientific schools and there 

 were a few strong men at work, yet chem- 

 istry in general, and water in particular, 

 were far from satisfactory. 



My note-book, dated 1872-73, contains, 

 so far as my knowledge goes, the records of 

 the earliest so-called sanitary analyses. 

 About this time the method of reducing 

 to grams was changed to milligrams, and 

 when finally accepted produced astounding 

 results. 



The cause of the great discredit to water 

 analysis in the '80 's was diie to the taking 

 up of the quick and comparatively simple 



