July 28, 1922] 



SCIENCE 



117 



was made with both warm and cold sulfuric acid 

 and the acid removed by dialysis, leaving the 

 acid-free base in a form suitable for testing its 

 decolorizing power. 



Color and ash absorption iy toneblack and 

 decolorising carhons: "W. D. Horne. While a 

 number of very good decolorizing carbons have 

 been developed, they generally lack the power to 

 absorb ash, which is of great importance in sugar 

 refining. Experiments show that it is the mineral 

 frame-work in boneblack which absorbs most of 

 the ash taken up by boneblack. Calculation 

 shows that a carbon deficient in ash absorbing 

 power could scarcely compete economically with 

 boneblack in refining. Encouraging results in 

 ash as well as color absorption were had with an 

 artificial boneblack formed by the fixation of 

 carbon on a porous earthy substratum. The 

 attention of investigators is invited in this direc- 

 tion. 



Control of reaction in sugar house (and re- 

 finery) liquors: J. F. Bbewster and W. G. Raines, 

 Jr. No matter what clarifying agent was used, 

 in the clarification of cane juice, there always 

 was obtained upon concentration to sirup a pre- 

 cipitate changing in quantity and composition 

 according to the cleanness of the cane and the 

 method of clarification. 



The precipitate formed in sugar house sirups: 

 J. F. Brewster and W. G. Raines, Jr. 



Modifications in the use and application of the 

 Hess-Ives tint photometer: H. H. Peters and 

 F. P. Phelps. In addition to the Hess-Ives 

 color plate, various "Wratten light filters were 

 used in connection with white light. It is point- 

 ed out that special lamps (for instance, a mer- 

 cur}' vapor lamp in place of white light) may ad- 

 vantageously be employed with special light fil- 

 ters in place of the Hess-Ives three fundamental 

 colors (red, green and blue), for instance, mer- 

 cury yellow, green and violet. One then obtains 

 scale readings (per cent, transmittancy), which, 

 interpreted as negative logarithms, refer to def- 

 iuite wave-lengths instead of to broad spectral 

 bands. The color values of the Hess-Ives plate 

 and of several Wratten filters are plotted as 

 transmittancies and luminosities, which were also 

 given for Stammer standard color plates. Stam- 

 mer's ulmine solution and various sugar products. 

 Their absorption graphs are given also. The 

 authors use the subject of tint photometric anal- 

 ysis as introduction to their spectrophotometrie 

 investigations. In three of the papers given so 

 far, the chemical aspect of color analysis was 



discussed, while here the optical aspect is treated 

 in detail. Hundreds of quantitative spectropho- 

 tometrie analyses of sugar products have proven 

 conclusively that the absorption and transmit- 

 tancy in the blue end of the spectrum is of para- 

 mount importance. 



Color values of high grade sugars: W. B. New- 

 kirk and H. H. Peters. The absorption and 

 transmittancies of 204 high class sugars were 

 determined for yellow, green and violet mercury 

 light, using a Stammer colorimeter which had 

 been modified in such a manner that it was prac- 

 tically a spectrophotometer. The Stammer color 

 plate was entirely dispensed with, and a rotating 

 sector disc used in its place. The average results 

 of various classes of sugars are plotted in various 

 ways. 



A laboratory vacuum still: E. P. Clark. A 

 laboratory vacuum still is described which is of a 

 simple tj-pe of construction and is compact and 

 easily dismantled. The capacity is quite large 

 (12 liters), concentration taking place in glass. 

 An ordinary laboratory water pump furnishes 

 sufficient vacuum. 



Preparation of adonitol: R. S. Black. Crystal- 

 line adonitol is prepared by extracting adonis 

 vernalis plants with hot water, defecating the 

 expressed liquid by first adding aluminum sulfate 

 solution followed by an excess of slacked lime 

 until precipitation is complete. The yellow pre- 

 cipitate is removed by fitering upon a suction 

 filter. Concentrate the filtrate in vacuum to a 

 tliin sirup when basic lead acetate is added, filter, 

 remove the excess lead, concentrate to a sirup and 

 add alcohol. At this point a little phosphoric 

 acid added to the alcoholic solution throws out 

 more impurities and aids in the subsequent 

 crystallization. The alcoholic solution is evap- 

 orated to a thick sirup and taken up in an equal 

 volume of 95 per cent, alcohol, is seeded and is 

 allowed to crystallize. RecrystalHze from 95 per 

 cent, alcohol. 



division of industrial and engineering 

 chemistry 

 W. K. Lewis, chairman 

 E. M. Billings, acting secretary 

 Symposium on Distillation 

 W. A. Peters, Jr., chairman 

 Efficiency and capacity of fractionating col- 

 umns: W. A. Peters, Jr. The efficiency of plate 

 columns and columns filled with spheres and 

 cTlinders of various sizes was measured by com- 

 paring the performance of each with the calcu- 

 lated performance of a theoretically perfect col- 



