CHEMICAL SCIENCE. 203 



it could be precipitated at once by sulphuretted hydrogen and quan- 

 tity weighed. 



To those who know anything of the immense difficulties of sepa- 

 rating such a body as arsenious acid from organic matter, by the pro- 

 cesses commonly adopted in the laboratory, the value of this process 

 will at once be obvious ; for a natural separation of the suspected sub- 

 stance is not merely procured, but the analysis is made without the 

 slightest loss of substance, and by repetition of the process the natural 

 separation may be perfected. It remains for our analysts to deter- 

 mine by direct experiment how far this simple method of inquiry may 

 be extended to every other body of the crystalloidal type. 



Finally, the labors to which we have drawn attention have an 

 immediate bearing on the phenomena of life, and on those changes 

 known as nutritive and excretive. As the colloidal condition is a 

 dynamical state of matter, so Prof. Graham suggests that it may be 

 looked on as the probable primary source of the force appearing in 

 the phenomena of vitality as living matter without form ; while to the 

 gradual manner in which colloidal changes take place (for they always 

 demand time as an element) may the chronic nature and periodicity 

 of vital phenomena be ultimately referred. 



INCREASING THE ILLUMINATING POWER OF GAS. 



It has long been known that the light of illuminating gas may be 

 considerably increased by mixing with the gas the vapor of naphtha, 

 benzole, or some other volatile hydro-carbon resulting from the de- 

 structive distillation of coal. As this vapor condenses at low tempera- 

 tures, it cannot be carried through pipes from the gas works, but must 

 be mixed with the gas in the vicinity of the burner. 



A late number of the London Chemical News contains a report of 

 a series of experiments made in London by Mr. W. Haywood, a gas 

 engineer, to test the advantage of applying this mode of increasing 

 light to the street lanterns. Moorgate Street was selected for the 

 experiment. Six lanterns on one side were provided with the common 

 batswing burners, burning five cubic feet of gas per hour, and six 

 upon the other side of the street were fitted with thirty-inch burners and 

 with reservoirs of naphtha. The experiment lasted thirty days. The 

 district inspector of the Commission, who saw the lights nightly, 

 reports his opinion that the light on both sides was perfectly equal. 

 Mr. Haywood thinks that the light from the thirty-inch burners was in- 

 ferior, though very slightly so, to that from the five feet burners. He 

 comes to the conclusion that about three feet of the carbonized gas is 

 about equal to five feet not carbonized. As the naphtha will not 

 evaporate in cold weather, the apparatus will not operate out of 

 doors in the winter, but Mr. Haywood thinks that it will save at 

 least five dollars to each street lantern during the summer months. 







COLOR PRODUCTS OF COAL TAR. 



Aniline, first discovered in coal tar by Dr. Hoffman, is now most 

 extensively used as the basis of red, blue, violet, and green dyes. 

 This important discovery will probably in a few years render Great 



