BITUMEN 353 



surface boiled, in large bubbles. The ascent to the lake from the sea, a distance of three- 

 quarters of a mile, is covered with a hardened pitch, on -which trees and vegetables 

 flourish ; and about Point la Braye, the masses of pitch look like black rocks among the 

 foliage : the lake is underlaid by a bed of mineral coal. (Manross, quoted by Dana.) 

 The Earl of Dundonald remarks, that vegetation contiguous to the lake of Trini- 

 dad is most luxuriant. The best pine-apples in the West Indies (called black pines) 

 grow -wild amid the pitch. 



Asphaltum, or solid bitumen, is abundant on the shores of the Dead Sea. It 

 occurs in the mountain-limestone of Derbyshire and Shropshire, and has been found in 

 granite, with quartz and fluor spar, at Poldice, in Cornwall. There is a remarkable 

 bituminous lime and sandstone of the region of Bechelbronn and Lobsann, in Alsace. 

 From the observations of Daubr^e, we learn that probably this bitumen has had its 

 origin as an emanation from the interior of the earth ; and indeed, in Alsace, with 

 the great elevated fissure of the sandstone of the Vosges, a fissure which was certainly 

 open before the deposit of the Trias, but was not yet closed during the tertiary epoch, 

 affording during this latter, moreover, an opportunity for the deposition of spathic 

 iron ore, iron pyrites, and heavy spar. Annales des Mines. 



Bituminous limestones are also found abundantly at Pyrimont, near Seyssel, in the 

 Dep. de 1'Ain, France, and in the Val de Travers, Neufchatel, in Switzerland. Both 

 these rocks have been worked for the sake of their bitumen. 



In addition to the bituminous substances already mentioned asphalt, naphtha, and 

 petroleum there are a number of closely related minerals, such as pittasphalt and 

 maltha, or mineral tar ; elaterite or elastic bitumen ; hatchettine, or mineral tallow, 

 ozocerite, &c. The more important of these are described under their respective 

 names. 



Of ordinary bitumen, we give ultimate analyses of two specimens : one by Ebelmen, 

 who obtained his sample from the Auvergne ; and the other by Boussingault, of a 

 Peruvian specimen : 



Anvergne. Peruvian. 



Carbon .... 76-13 . . 88-63 

 Hydrogen , 9'41 . . 9'69 



Oxygen .... 10-34 1 .. 68 



Nitrogen .... 2-32 / * 

 Ash . 1-80 



100-00 100-00 



Bitumen in many of its varieties was known to the ancients. It was used by them 

 combined with lime, in their buildings. Not only do we find the ruined walls of 

 temples and palaces in the East, with the stones cemented with this material, but 

 some of the old Roman castles in this country are found to hold bitumen in the 

 cement by which their stones are secured. At Agrigentum it was burnt in lamps, and 

 called ' Sicilian oil.' The Egyptians used it for embalming. Dana. 



On the employment of bitumen for pavements, Dr. Ure has the following remarks : 

 It is a very remarkable fact, in the history of the useful arts, that asphalt, which 

 was so generally employed as a solid and durable cement in the earliest constructions 

 upon record, as in the walls of Babylon, should for so many thousand years have 

 fallen well nigh into disuse among civilised nations. For there is certainly no class 

 of mineral substances so well fitted as the bituminous, by their plasticity, fusibility, 

 tenacity, adhesiveness to surfaces, impenetrability by water, and unchangeableness 

 in the atmosphere, to enter into the composition of terraces, foot-pavements, roofs, 

 and every kind of hydraulic work. Bitumen, combined with calcareous earth, forms 

 a compact semi-elastic solid which is not liable to suffer injury by the greatest 

 alternations of frost and thaw, which often disintegrate in a few years the hardest 

 stone, nor can it be ground to dust and worn away by the attrition of the feet of men 

 and animals, as sandstone, flags, and even blocks of granite are. An asphalt pave- 

 ment, rightly tempered in tenacity, solidity, and elasticity, seems to be incapable of 

 suffering abrasion in the most crowded thoroughfares ; a fact exemplified of late in a 

 few places in London, but much more extensively, and for a much longer time, in 

 Paris. 



The great Place de la Concorde (formerly Place Louis Quinze) is covered with a 

 beautiful mosaic pavement of asphalt ; many of the promenades on the Boulevards, 

 formerly so filthy in wet weather, are now covered with a thin bed of bituminous 

 mastic, free alike from dust and mud ; the foot-paths of the Pont Royal and Pont 

 Carousel, and the areas of the great public slaughter-houses, have been for several 

 years paved in a similar manner with perfect success. It is much to be regretted that 

 the asphalt companies of London made the. ill-judged, and Dearly abortive, attempt 



VOL. I. A A 



