1843.] aud Hydraulic works in India. 537 



naptha have been destroyed by volcanic agency, and the material is 

 not liable to ignition. The calcareous asphalte contains from 15 to 18 

 per cent, of bitumen, the remainder is carbonate of lime. The bitumen 

 from the results of experiments of a French chemist is found to be a 

 compound of 



Resinous petroliferous matter, ... ... 60 to 70 



Carbon, 30 to 35 



It is from the carbon that the dark color and property of hardening 

 in the air arises which renders it so useful in the arts. The spaces 

 below the carbonate of lime are fissures containing the mineral pitch, 

 which is formed of the heavier particles of bituminous matter and 

 carbon in another form, probably having experienced greater heat. As 

 used in England and the continent, the asphalte is reduced to powder 

 by baking, and being mixed with a proportion of about one-tenth its 

 weight of the pitch and a fine grit, is reduced to a semifluid state, and 

 poured on to the spaces or moulds prepared. 



For exportation, however, the substances are formed by the Company 

 in England into a mastic, and sent to distant parts in blocks of a cwt. 

 each ; by this means it is rendered useful to those who may not have 

 had the advantage of witnessing the mode of application in England, 

 as the mastic has merely to be heated, and laid down in the way which 

 will be described hereafter. The mastic possesses nearly the hardness 

 of stone, but preserves a certain elasticity which prevents the surface 

 from wearing or chipping, and carriage wheels and horses' hoofs cannot 

 disturb the evenness and regularity of its surface. Not the least of its 

 valuable properties as a material for building purposes in India, is the 

 facility of its removal from place to place ; after having been laid down 

 as a terrace in one building for years, it may be taken up, and re- 

 quires merely to be reheated to be laid down elsewhere with equal 

 utility. It is anti-electric, which makes it valuable for roofing pur- 

 poses, and is not inflammable, the quantity of pitch being so small. 

 The late fire at Hamburgh is proof of the non-inflammability of the 

 material, for the roofs of many houses were terraced with it, and 

 great alarm existed lest these roofs should burn and cause more 

 devastation ; they fell in solid masses unconsumed, and instead of serv- 

 ing as fuel, extinguished in their fall, the flames beneath them. It is 

 wholly impervious to moisture, and can be extended indefinitely, and 



