248 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



is roughly estimated to yield a million cubic feet of gas ev- 

 ery twenty-four hours ; and this is only one of many laro-e 

 gas wells, and almost numberless small ones; for it must be 

 remembered that every well which produces oil yields gas 

 also. A survey has just been completed for a line of pipe 

 from Sarnersville to Pittsburgh, a distance of about seventeen 

 miles. It is proposed to lay a six-inch pipe between the 

 points named, and to supply the gas to the manufacturing 

 establishments in Pittsburgh as a substitute for coal. 



MELANOSLDEEITE, A NEW MINERAL. 



Professor Cooke, of Cambridge, has described a new min- 

 eral under the name of Melanosiderite. It is compact and 

 amorphous, very brittle, and with a conchoidal fracture. 

 Its lustre is vitreous, color black, and streak brownish-red. 

 In hardness it lies between fluor-spar and apatite, and its 

 specific gravity is 3.39. An analysis shows it to consist 

 essentially of silica, iron, and water ; and Professor Cooke 

 regards it as a very basic silicate of iron, most closely al- 

 lied to Ilisingerite. It comes very near to the common 

 sesquihydrates of iron, but its low specific gravity is re- 

 garded as showing a marked distinction from them. It was 

 found in Chester County, Pa. 



Professor Cooke has also continued his investigations of the 

 vermiculites, and has described two new varieties, one from 

 Delaware County, Pa., the other from Pelham, Mass. His 

 labors on this group of minerals have led him to the con- 

 clusion that they are all unisilicates, and combine with water 

 in several definite proportions, but that the only essential 

 difference between them is in the ratio between the sesqui- 

 oxide and protoxide bases. 





