1876.] -^11 [Sadtler. 



plus values for x, y, and z, but the previous qualitative tests liad shown 

 conclusively the presence of Cj Hg. 



I found, however, unexpectedly in Fonqu6's memoir the strongest con- 

 firmation of my interpretation of my results. Using the three equations 

 that I have given above, he finds that when x, y, and z represent three suc- 

 cessive members of the marsh-gas series, the equations are as follows: 



X + Y + z=Y. (1). 

 X +2y+ 33 = C. (2). 



5 



2«+ ^+32 = A. (3). 



from which can be deduced as a fourth equation. 



2 A — 3V = C. (4). 



In other words, when an eudiometric analysis of a mixture of hydro- 

 carbons of the marsh-gas series is made, the carbonic acid formed is equal 

 to twice the contraction, mmus three times the volume of gas taken. 



He says, therefore, (Compt. rendus. LXVII. p. 1048) when the marsh-gas 

 hydrocarbons are mixed with free hydrogen, this fourth equation is not 

 realized. I did not find it realized in any of my analyses. Thus in the 

 analyses of the Burns Well gas, I had the following figures : 



I. II. 



Gas taken 32.74 24.49 



Contraction 70.4 52.75 



COj absorbed 36. 6 27.5 



If we substituted the values of C and V as found, in the formula 

 2 A == C -f 3V, we get, for the first, 36.6 -f 98.22 = 134.82, of which the 

 half is 67.41. But the observed contraction is 70.4, or 2.99 greater than 

 that demanded by Fongu6's formula for the marsh-gas hydrocarbons. So 

 for the second we get 27.5 + 73.47 = 100.97, of which the half is 50.485, 

 while the observed contraction is 52.75. 



If now we turn to to the formulas first stated by me, we find the explana- 

 tion in the third equation where we have 3x, assuming x to be hydrogen ; 

 and in the second equation where we have Ox, assuming x to be hydrogen. 



I have not been able as yet to make any experimental determinations of 

 the specific gravity of these gases, but have the material reserved, and 

 expect to do so. The specific gravities as calculated from the analyses 

 given, are as follows : 



Sp. gr. 

 Burns Well gas 6148 



Mr. Lesley mentioned that Mr. Hall had found three casts 

 of an Orthis of the Trenton (Bala) Limestone in a sub- 

 angular fragment among the moraine (?) matter cut into for 

 a drain in front of the University buildings in West Phila- 

 delphia. 



