238 ANNUAL OF SCIENTIFIC DISCOVERY. 



tion of eight ounces of rosin to one gallon of oil, and applied a moder- 

 ate heat, sufficient to produce perfect solution. I then filled two solar 

 lamps, equal in all respects, the one with lard oil, the other with the 

 same holding the rosin in solution, and regulated the flame, so as to 

 be as nearly of the same size as possible. I measured, by the metliod 

 of shadows, the comparative intensities of light, which I found to be 

 as 7 to 5 in favor of the prepared oil. This burned with a flame of 

 peculiar richness, plainly exceeding in density that from the simple 

 oil, but after two hours the flame of the prepared oil began to decline 

 slowly, and soon became inferior to the other, an effect which doubt- 

 less arose from the clogging of the wick. I had hoped, on account of 

 the perfect solution which the rosin seemed to undergo, that the com- 

 pound would burn freely without encountering this impediment ; but 

 in this respect I was disappointed, and can only say that, if some means 

 can be devised for avoiding the tendency to clog the wick, the addition 

 of a small portion of rosin to lamp-oil or lard will add essentially to 

 its value for burning in solar lamps, by rendering it less liable to con- 

 geal, and by increasing its illuminating power. 



FORMULA FOR AN INK THAT RESISTS THE ACTION OF ACIDS, 

 ALKALIES, WATER, OR ANY OF THOSE SUBSTANCES USUALLY 

 USED IN DEFACING WRITING. 



SHELL-LAC 2 oz. ; borax 1 oz. ; distilled or rain \vater 18 oz. Boil 

 the whole in a closely covered tin vessel, stirring it occasionally with 

 a glass rod until the mixture has become homogeneous ; filter when 

 cold, and mix the fluid solution with an ounce of mucilage of gum 

 Arabic prepared by dissolving 1 oz. of gum in 2 oz. of water, and add 

 pulverized indigo and lampblack ad libitum. Boil the whole again 

 in a covered vessel, and stir the fluid well to effect the complete solu- 

 tion and admixture of the gum Arabic. Stir it occasionally while it is 

 cooling ; and after it has remained undisturbed for two or three hours, 

 that the excess of indigo and lampblack may subside, bottle it for use. 

 The above ink for documentary purposes is invaluable, being, under 

 all ordinary circumstances, indestructible. It is also particularly well 

 adapted for the use of the laboratory. Five drops of creosote added to 

 a pint of ordinary ink will effectually prevent its becoming mouldy. 



GAS FROM WATER. 



AFTER many partial and conflicting statements, we have at last 

 minute detailed accounts of the manner in which a gas for burning is 

 produced from water by Mr. H. M. Paine, of Worcester, Mass. 

 These accounts are contained in the Boston Chronotype, Springfield 

 Republican, and Boston Transcript, and it is from all of these that the 

 following facts are derived. 



Mr. Paine claims, among other things, to have discovered a means 

 of increasing the power of a magneto-electric machine, to such an 

 extent that he can decompose water rapidly with it ; that he can take 

 a jar of water, and, by means of the electricity induced by this ma- 



