512 SCIENTIFIC RECORD FOR 1884. 



noted an abnormal foatiire, viz, the rise in temperature from 55° to 62^, 

 8(P to 90°, and 10')° to 110° was accompanied by a decrease in the spe- 

 cific gravity- of the portions distilling at the temperatures named. A 

 carefully conducted fractional distillation of petroleum of American 

 origin showed that this has the same peculiarity. The petroleum was dis- 

 tilled in an apparatus arranged so that the result was equivalent to 50 

 simple distillations. At 00° very little distilled over, the specific grav- 

 ity was 0.6G42 at 17° C. and rose to 0.7347 at 80° C, products being 

 collected separately ever}' 2° of rise. The first decrease in specific 

 gravity occurred at 92°, the distilhite showing at 75° a specific gravity 

 of 0.7060. A regu'ar increase in the specific gravity followed up to 

 104°, at which point the specific gravity was 0.7543; then a decrease 

 was noted, the distillate at 115° to 117° having the specific gravity 

 0.7270. From 11 7° to 125"^ the specific gravity increased regularly. 



The author ascribes the failure of others to notice this peculiarity to 

 the lack of delicacy in the distillations previously conducted. [Protok. 

 d. Bvss. phys.ehem. Ges., 1884, 458.) 



Composition of Chlorophyll. — Dr. Adolph Hansen has published im- 

 ])ortant investigations on the nature of chlorophyll. Chemists will re- 

 member that Fremy claimed that green chlorophyll consisted of a blue 

 and a yellow constituent. He mixed an ethereal chlorophyll solution 

 with hydrochloric acid, when two layers formed, a lower blue layer 

 and an upper yeUow ethereal layer ; the blue coloring mjitter was named 

 by Fr6my phyllocyauin and the yellow phyUoxanthin. Hansen shows, 

 however, that this is not due to a splitting up of the chlorophyll green 

 into a blue and a yellow component, but only an incomplete separation 

 of the chloroi)hyll green from the chlorophyll yellow, the former becoin- 

 iug changed to blue by the hydrochloric acid. He further shows that 

 an ethereal solution of pure chloroi)hyll green treated with hydrochloric 

 acid does not furnish any yellow constituent, the ethereal layer remain- 

 ing colorless. 



It will be remembered that Kraus also supposed he had decomposed 

 chlorophyll green into a blue-green and a yellow component; he called 

 the blue-green cyanophyll, the yellow body xanthophyll. Hansen shows, 

 however, that Kraus is wrong, and his supposed decomposition is only 

 an incomplete separation, and that his cyanophyll is nothing more than 

 an ordinary chlorophyll solution from which a part of the yellow color- 

 ing matter has been removed. Both Fremy and Kraus were correct in 

 assuming the existence of yellow and of green bodies, but mistaken in 

 supposing they existed in combination. Hansen shows that they exist 

 side by side, and that chlorophyll is a mixture of these coloring matters. 



Inpreparing pure chlorophyll Hansen used the leaves of young wheat- 

 plants. These are first boiled to remove extractives, the water is 

 decanted, and the material waslied ; it is quickly dried at a low tem- 

 perature, and then extracted with alcohol of 90 per cent., iu a dark room^ 



