THE SOURCE OF LIOHT, HEAT, COLOUR, ETC. 223 



possesses the exact odour of oil of bitter almonds, and is sometimes sold 

 under that distinctive. Its formula approximates very closely to the 

 genuine oil of almonds, which is, in fact, a hydride of benzole : 



Oil of Almonds, C 12 H s 2 . 



Nitro-benzole, Ci 9 H 5 N.0 4 . 

 Nearly all the essential oils are simple compounds of hydrogen and carbon ; 

 and, in order to produce them artificially from the products of the fossil 

 hydro-carbons, there must be the necessary re-arrangement of the particles. 

 To induce this result in the most facile and inexpensive manner, is a 

 work in which our chemists will not fail eventually to excel. 



Some attention has been bestowed upon the fossil hydro-carbons, as 

 being useful solvents for varnish-making, and in the treatment of elastic 

 gums, &c. Naphtha has long been employed in the preparation of cheap 

 polish, and a common varnish is produced with Rangoon tar and gum 

 dammar, but it is the light paraffine spirit which promises the most im- 

 portant results in this direction. The oils having a lighter specific gravity 

 than '750, were not long since regarded as waste products, and, in some 

 branches of manufacture, were either allowed to run away, or were employed 

 in the processes connected with the preparation of the burning fluids. 

 Found, however, to be available for more useful purposes, there was at first 

 a demand, suddenly, rather in excess of the supply. This light spirit is 

 an excellent solvent for resins of all kinds, and is a good substitute for 

 turpentine in the mixing of paints, and will doubtless be employed in this 

 way to a considerable extent. To fit it for use, it has to undergo some 

 manufacturing process, by which it is altogether purified and separated 

 from any of the paraffine oil it may contain, if not chemically changed. 

 These fluids are highly inflammable, and the gaseous vapour which con- 

 tinually rises from them readily ignites if the flame of a candle be brought 

 within its reach. One variety of this bight spirit, purified, is in the market, 

 under the distinctive of Turpentole. 



The cementing and concretionary properties of the bitumen have also 

 attracted much notice of late, and the application of asphalte in combina- 

 tion with sand for pavements, and in conjunction with hair-felt for roofing 

 is very considerable, several public companies for developing these branches 

 of fossil hydro-carbon industry having started into existence. With 

 the example before us of the bricks in Babel's tower cemented with bitumen, 

 I wonder no attempt has yet been made to utilise these same products in 

 this way amongst ourselves. Many of the asphaltes are both cheap and 

 abundant, and there is also a large amount of coal-tar produced in the 

 country, which, although not natural bitumen, is a good artificial one, and 

 I should suppose must possess identical properties. Surely for the founda- 

 tion work of bridges, or of buildings in general, bituminous cement would 

 be preferable, and more durable than those kinds commonly in use. The 

 little coffin of rushes plastered with pitch (bitumen) in which the infant 

 Moses was hidden at his mock funeral, furnishes another indication of the 



