Polytechnic Association. 711 



Dr. J. "W. Richards — After charcoal has absorbed its full amount 

 of one gas, it will absorb about the same quantity of another. I have 

 stopped the decay of a tooth by whittling a plug of charcoal and put- 

 ting it in. Charcoal undoubtedly tends to prevent flatulence ; but I 

 think it is not from its power of absorption. Like mustard, it proba- 

 bly stimulates the stomach. 



Mr. T. D. Stetson — Charcoal has been fed to cattle, mingled with 

 meal, with good effect, for many years. The theory of decay is that 

 one particle starts another. Charcoal promotes eremacausis, or slow 

 combustion ; and the moment a particle begins to decay, it resolves 

 it into gases and leaves the rest sweet. 



Dr. J. W. Richards — Carbon is perfectly indigestible. In the lungs 

 of miners it accumulates so as sometimes to destroy life, showing that 

 it is indestructible in the system. 



IV. Mellithic Acid. 



Prof. Schultze recently made an announcement at a recent meet- 

 „ ing of a German association, which was received with enthusiasm, 

 it being regarded as a pioneer research in a new field, which is likely 

 to be of great importance in applied chemistry. He has succeeded 

 in obtaining mellithic acid by the direct oxidation of carbon with per- 

 manganic acid in alkaline solution. Oxalic and other acids had been 

 also produced previously by the same process. Mellithic acid was 

 obtained from various forms of carbon, including graphite, which, 

 on distillation with soda-lime, gave benzole, and the latter upon nitra- 

 tion and subsequent reduction yielded analine. 



V. New Form of Sensitive Flame. 

 Mr. Philip Barry, of Cork, Ireland, has devised a new method of 

 making a sensitive flame, of which he writes to Prof. Tyndall as fol- 

 lows : " It is in my experience the most sensitive of all sensitive 

 flames ; though, from its smaller size, it is not so striking as your 

 vowel flame. It possesses the advantage that the ordinary pressure 

 in the gas mains is quite sufficient to develop it. The method of pro- 

 ducing it consists in igniting the gas (ordinary coal gas), not at the 

 burner, but some inches above it, by interposing a piece of wire gauze 

 between the burner and the flame. The piece of wire gauze (thirty- 

 two meshes to the inch) is supported about two inches above the 

 burner. On turning on the gas and lighting it above the gauze a 

 flame is obtained in the shape of a slender cone, four inches high, the 

 upper portion giving a bright yellow light, the base being a non-lumin- 



