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THE POPULAR SCIENCE MONTHLY. 



The mineral appears in industry, under a still more useful form 

 than the compressed form, as asphaltic mastic. This is made by throw- 

 ing the powdered mineral into a bath of seven or eight per cent, of 

 its weight of liquid bitumen, and mixing the whole thoroughly while 

 it is cooked for live or six hours. The substance produced, although 



chemically the same, except for the difference in the relative propor- 

 tions of bitumen and limestone, is physically entirely different from 

 asphalt. It can not be pulverized by heating, but forms a paste in 

 which the two ingredients seem to be perfectly combined, and which 

 may be molded into desired forms. The manufacture of the mastic 

 has become an important industry. The annual production of the 

 French shops alone must amount to fifteen or twenty thousand tons. 



In " La Nature," of April 9th, Mr. A. Woeikofen, of St. Petersburg, 

 describes the asphaltic beds of Russia, which occur on the grand curve 

 of the Volga, or the arc of Samara, a short distance above the city of 

 Syzran. They are not deposited in the Jurassic formation, as are those 

 in France, Switzerland, and Germany, but in a dolomitic limestone of 

 the lower Carboniferous series. The mineral is rich in bitumen, of 



