222 BITUMEN, ASPHALTUM, PETROLEUM, ETC. 



According to Gesiier the surface of the lake is occupied bj small ponds 

 of clear water, in which are found several kinds of beautiful fish.* This 

 remarkable lake is said to repose on recent Tertiary beds — Miocene and 

 probably Pliocene. The odor of the mineral is apparent in the atmosphere, 

 and it is asserted that it can be detected at eight miles distance. The bitu- 

 men, according to Gesner, yields by distillation a whole series of hydro- 

 carbon oils, and gives seventy gallons of crude oil per ton of 2240 pounds. 

 It is much valued lor ship bottoms, and is reported to kill the teredo. 



GERMANY. 



The as^Dhaltum of Werwohlen, Brunswick, is found in a sandstone which 

 is said to be of Tertiary age. It very nearly resembles the bituminous 

 sandstone of the coal measures of Southwest Missouri. It is used for roof- 

 ing, for which purpose it is said to be well adapted, as it does not melt 

 under ordinary sun exposure, and in the preparation seven-eighths inch as- 

 phalt is laid on three and one-half inches of cement. 



SPAIN. 



At Mastu, Yittoria, there occurs a-fine-grained, black, bituminous lime- 

 stone, and from it is made refined asphaltum. 



SWITZERLAND. 



The asphalt from Val de Travers has a world-wide reputation as a pav- 

 ing material. It is said not to crack in cold weather, being not affected by 

 changes of the weather, nor does it possess a bad odor. Parkinson, in 

 1804, stated that en the south side of a mountain, the northern declivity of 

 which terminates in the Yalley of Travers, between Travers and Couvet, 

 near to Neuenberg, there are two large pits containing asphaltum, which, 

 in 1758, had been worked upwards of forty years. At the same height, on 

 the other side, it was also found. 



At Neuchatel it occurs, impregnating a limestone bed in the cretaceous 

 formation, and serving as a cement to the rock, which is used for buildings. 

 The rock is quite black and strongly impregnated with it. The Neuchatel 

 limestone at this time (1876) has been worked for forty years, and is ex- 

 tensively used throughout Europe for paving and for roofing jDurposes. 

 The principal agency is in London, but the asphaltum is used in ail the 

 chief European cities. In London it is found better to use it in a j)ure 

 state. In Paris it is very much used, where it is mixed with rock. The 

 Swiss Commissioner at the Centennial informed me that he had an acre 

 paved with it at Neuchatel that had been in use for fifteen years without 

 repairs. In Switzerland the preparation for roofing is generally: (1.) Flat 

 tiles are laid in mortar on an inclined roof. (2.) Then pure asphalt i§ 

 poured on to the depth of an inch. (3.) Then clean gravel is j)laced on the 

 iisphalt as closely as possible, causing it to present the appearance of a 



* Coals'., oils, etc., by Gesner. 



