462 PROFESSOR A. SCHUSTER AND MR. W. GANNON ON A 
value. verything in the experiments depended on the measurement of a couple, 
the arm of the couple being the distance between two knife-edges, one of which had 
to support a weight of more than 43 kilos. The distance between the knife-edges is 
said to have been 28 centims. in all experiments. Very insufficient information is 
however given how that distance was measured, and it would almost seem as if the 
author had trusted to the maker in adjusting the central knife-edge to the zero 
point of its scale. If the apparatus is still in existence it might be well to make 
sure that no error has been introduced through a wrong estimate of the length of 
the lever arm. 
In order to compare Micunescu’s value with that of others we must apply a 
temperature correction which is somewhat doubtful, but taking the mean of Row- 
LAND’S and GRIFFITHS’ values as the most probable at present, we obtain at 15° the 
following values :— 
TasLe X VI.—Equivalents in foot-pounds at Greenwich, at 15°, referred to the 
“ Paris ” nitrogen thermometer. 

ScHUSTER and 
LE. ROWLAND. MIcULESCU. GRIFFITHS. 
Jou D GANNON. 


775 778:3 7766 780°2 779-7 

If we remember that RowLanp’s number referred to the “ Paris” nitrogen 
thermometer would probably be smaller by one unit, we are struck with the fair 
agreement there is on one hand between the results of JouLE, Rownanp, and 
Micuxescu, and, on the other hand, between GRIFFITHS and ourselves. As far as 
we can draw any conclusions from the comparison, it seems to point to a difference in 
the value obtained by the electrical and direct methods. Whether this method is 
due to some remaining error in the electrical units or to some undiscovered flaw in 
the method adopted by Mr. Grirrirus and ourselves remains to be decided by 
further investigations. 
