270 E. Billings on a Question of Priority. 
wave-lengths of these vibrations 4°367 and 4°401 feet, which we 
will designate in order as A and A’ We will take 1118 feet per 
second as the velocity of sound at 60° Fahr. 
Now 256 vibrations in 1118 feet make 14-367 feet. 
and 254 “ 1118—2A (=1109-266) give A=4°367 feet. 
As the velocity of propagation of the vibrations and A are the 
same in both cases, it follows that (n a =) the number of vibra- 
tions in a second, reaching a distant point, is the same, and, 
therefore, 256 vibrations from a body at rest will produce the 
same effect on a distant surface, as 254 vibrations emanating 
from a body which moves toward that surface, with a velocity 
of 2A, or of 8°734 feet per second; and this is the velocity we 
gave the fork in Exps. 6 to 9. 
We will now examine the analogical phenomena in the case 
of light. Let fork No. 1, giving 256 vibrations a second, stand 
February 8th, 1872. 
Art. XXXVI.—WNote on a Question of Priority ; by E. BILLINGS, 
Paleontologist of the Geological Survey of Canada. 
In the Canadian Naturalist, published on the 29th of Dec, 
1871, I proposed two new genera of Brachiopoda, Monomerella 
Ww 
*The form here alluded to is fig. 20, p. 189, of the report. It shows the it- 
terior of a dorsal valve imperfectly. This may not be 0. Canadensis; but @ 
Segre I think it is. Should it be otherwise, it does not affect the question. 
The fossil will only require ano ific name. 
