2Ub THE TECHNOLOGY OF SOME OP 



Dr. Ashby, in the ' Mechanics' Magazine,' gives an entirely new ap- 

 plication for carbolic acid, and thinks that it would be found useful in 

 grinding, tiling, boring, or sawing in metal work, on account of possess- 

 ing that which he calls " pro-frictional powers," as opposed to the 

 " anti-frictional powers " of oil, which keeps surfaces asunder by the 

 interposition of a thin fine film, whilst carbolic acid seems to bring 

 them together. The medicinal properties of carbolic acid have been 

 lately highly spoken of in diarrhoea, and in obstinate vomiting, 

 and in the proportion of one part to seven of water, has been 

 used with great success as a local application to fetid, ill-conditioned 

 ulcers, and speedily cures some skin diseases. It is said to be an effec- 

 tual remedy for the foot-rot in sheep. 



Naphthaline (C20 H s ) is another product of the distillation of coal, 

 and in cold weather condenses in the pipes in such quantities, that it has 

 been called the gas-maker's nuisance. When pure it is a beautiful white 

 crystalline substance, insoluble in water, but soluble in alcohol and ether. 

 By the action of the strong acids, especially the nitric, a large number 

 of substances of the highest interest to the chemist are produced. At 

 present no economic application has been found for naphthaline, which 

 the large quantity capable of being procured with facility renders very 

 desirable, it is true that by the action of various reagents, purple, violet, 

 yellow, shades of red and blue can be produced, yet on account of their 

 fugitive nature and incapability of being fixed so far, they are not com- 

 mercially successful for dyeing purposes. 



Paraffine (C'20 H20) is a solid crystalline substance existing in small 

 quantity in coal tar, but obtained for commercial purposes from the resi- 

 duum of the distillations carried on for the manufacture of illuminating 

 oils. After the lamp oil is separated, a heavy oil is left ; this being 

 submitted to a temperature of 30°, the paraffine solidifies, and is removed 

 by pressure, the liquid oil being used for lubricating machinery, &c. 

 After this separation the crude paraffine is purified by being submitted to 

 the action of sulphuric acid and soda alternately, and then appears like 

 spermaceti, being both tasteless and inodorous. The striking chemical 

 character of paraffine is the indisposition it possesses to combine with 

 other substances, and a power of resisting the action of the most powerful 

 reagents. Nitric and sulphuric acids do not affect it at ordinary tempera- 

 tures ; the same is the case with the alkalies, chlorine, &c. The fat oils, the 

 essential oils, and ether dissolve it readily, alcohol sparingly. Chemically 

 it is solid defiant gas, a fact which causes it to burn with a most bril- 

 liant, white, and clear flame. This latter property, coupled with a beau- 

 tiful appearance and remarkable transparency, constitutes it a formi- 

 dable opponent to wax and spermaceti in the manufacture of candles, 

 over both of which it possesses considerable advautages in regard to 

 transparency, high temperature of fusion, great illuminating power and 

 freedom from grease. The transparency enables the manufacturer to 

 produce coloured candles of paraffine with a quantity of colouring matter 



