CHEMICAL SCIENCE. 209 







tion, not attended by explosion ; nor can explosion be produced with 

 the vapor, excepting when we mix a little vapor with a large volume 

 of air and heat the mixture. Hence, practically, the standard oils 

 from the different sources named may be considered safe as fuel for 

 lamps used under all ordinary exposures ; and no accident has been 

 traced to the consumption of such oil, notwithstanding the very great 

 extension of its application at present in this way. 



The consumers of the standard oils obtained from coal and oil 

 springs should be assured that their supplies were purchased from 

 well-known, reliable manufacturers, and all mixtures of light spirits 

 with alcohol, fusel oil, and turpentine, under the numerous fancy 

 names now so common, should be rejected without hesitation. Any 

 one may apply a simple test of inflammability, by allowing two spoon- 

 fuls of the oil, contained in a tea-cup warmed to 75 or 80, to be 

 brought in contact with the flame of a lamp-lighter. No danger at- 

 tends the trial, and if the vapor or the oil will inflame, great risk will 

 be incurred in consuming it. 



True, explosions occur with the vapors of burning fluid, the light 

 napthas of oil-spring oils and their mixtures ; the use of which, since 

 pure coal oils have been introduced, is no longer economical, and has 

 always been attended by wanton sacrifice and exposure of human 

 life. " 



WEITING INK. 



M. de Champnor and M. F. Malepeyre, in their Manual, say that 

 Ribaucourt's ink is one of the best at present in use. The formula 

 for its preparation is as follows : 



Aleppo galls, in coarse powder, 8 ounces. 

 Logwood chips, . 4 " 



Sulphate of iron, 



Powdered gum-arabic, 

 Sulphate of copper, 

 Crystallized sugar, . 



4 " 



3 " 



1 " 



1 



Boil the galls and logwood together in twelve pounds of water for an 

 hour, or till half the water has been evaporated ; strain the decoction 

 through a hair sieve, and add the other ingredients; stir till the 

 whole, especially the gum, be dissolved; and then leave at rest for 

 twenty-four hours, when the ink is to be poured off into glass bottles 

 and carefully corked. 



Mr. J. Horsley gives the following receipt : Triturate in a mortar 

 thirty-six grains of gallic acid with three and one-half ounces of 

 strong decoction of logwood, put it into an eight-ounce bottle, to- 

 gether with one ounce of strong ammonia. Next dissolve one ounce 

 of sulphate of iron in half an ounce of distilled water by the aid of 

 heat ; mix the solutions together by a few minutes' agitation, when 

 a good ink will be formed, perfectly clear, which will keep good any 

 length of time without depositing, thickening, or growing mouldy, 

 which latter quality is a great desideratum, as ink undergoing that 

 change becomes worthless. It will not do to mix with ordinary ink, 

 nor must greasy paper be used for writing on with it. Chemical 

 News. 



New Indelible Marking Ink. Dr. Eisner gives the following as 

 18* 



