84 ANNUAL OF SCIENTIFIC DISCOVERY. 



purchased the patent-right, which has since been sold at auction to 

 different persons, and the whole produced about $ 520,000, showing 

 conclusively that confidence is felt in the value of this discovery. 



NEW MATERIAL FOR THE MANUFACTURE OF GAS. 



EXPERIMENTS have been recently made by Dr. Gesner, of Nova 

 Scotia, under the auspices of the Earl of Dundonald, with a view of 

 testing the applicability of the asphaltum furnished by the great pitch 

 lake of Trinidad, as a material for the manufacture of gas. In the 

 dry distillation of this substance, large quantities of carburetted hydro- 

 gen, similar to that employed for lighting, are produced. Some diffi- 

 culties have, however, hitherto prevented the application of the gas, 

 produced from this source, to the purposes of illumination. These 

 difficulties Dr. Gesner professes to have so far overcome as to be able 

 to manufacture a gas from asphaltum, much cheaper than from coal, 

 rosin, or any other hydro-carbon. In a communication to the Acade- 

 my of Natural Science he says: "It is remarkable that so rich a 

 hydro-carbon as asphaltum should have been so long overlooked, in 

 reference to its capabilities for affording light. It had been tried for 

 fuel, pavements, and for other purposes, both in Europe and the United 

 States, but without success. For what purpose nature had formed 

 such vast quantities of bituminous matter, which still continue to flow 

 from the earth, was a problem not readily solved, until this discovery, 

 which brings it into operation for illuminating purposes, to which it 

 is admirably adapted. In the analysis given by the chemists of Eu- 

 rope of the bitumen of Trinidad, there is a great diversity. Some 

 have stated that it contains twenty and even thirty per cent, of silex, 

 when in fact it seldom contains ten per cent. The specimens submit- 

 ted to their investigations must have been taken from the beach form- 

 ing the great pitch lagoon of the island, where the sand of the shore 

 is frequently mixed with the bitumen. The following table gives the 

 comparative quantities of volatile matter and carbon existing in coal 

 and bitumen : 



Volatile Matter. Coke, or Carbon. 



Bitumen of Trinidad, . . 65.50 36.57 



" Barbadoes, . . 61.60 36.90 



" Cuba, . . . 63.00 34.97 



" Yucatan, . . . 62.60 35.20 



Coal, best Cannel, . . 44.00 52.60 



" Liverpool, . . . 40.48 54.90 



For the production of gas, the advantages which bitumen possesses 

 over coal are numerous. Sulphur not being one of its constituents, 

 injurious and noxious gases are not produced in its decomposition, 

 and the absence of nitrogen prevents the formation of ammonia. The 

 ordinary time for the escape of the gas from a retort rilled with coal is 

 eight hours. During that period the retort must be kept at a bright 

 red heat, and labor and fuel are in constant requisition. The gas 

 from the same quantity of bitumen would be fully discharged in two 

 hours, whereby a saving of three quarters would be effected in fuel 



