456 PROFESSOR A. SCHUSTER AND MR. W. GANNON ON A 
In the second series of experiments, the coil was wound on porcelain strips, aud we 
were quite satisfied that the water equivalent was known with sufficient accuracy. 
Nevertheless the agreement of the results in this series is not satisfactory. 
In experiments 4 and 6 the thermometer was falling both in the first and last 
period, and the cooling correction was consequently somewhat large; on the other 
hand the lag of the falling thermometer would affect both the first and last period, 
and, therefore, be partly eliminated in the result. 
Experiment 5 is rendered a little uncertain by the fact that the thermometer at 
the beginning of the first period fell slightly, and then remained perfectly stationary ; 
it is therefore probable that the temperature was really increasing at the beginning of 
the experiment. The cooling correction, calculated on the assumption of no rise, 
would be too large, hence the calculated equivalent too small. The result of March 8th 
is anomalous, and does not seem altogether accounted for by the sticking of the 
thermometer at the end. There was on that day an exceptionally large difference 
in the amount of water, as measured by weight and by volume. We took, as 
usual, the mass as determined by weight ; had we taken the latter, the calculated 
equivalent would have been 4181. A final revision of our calibration correction 
showed a small error, which may have affected some of the results in series I. and 
II., by about one part in two thousand. As we do not attach any value to the 
numbers obtained, we have not recalculated the numbers. 
The results of our third series are as consistent as could be hoped for. We thought 
it useless to multiply the experiments, as it did not seem to us that our results could 
be materially improved by repetition. Their good agreement shows that our results 
are correct to more than one part in a thousand, provided that we have avoided 
systematic errors. The difference between our results and that of Mr. GRrrrriTHs 
must be due, on the one side or other, to errors which a multiplication of experiments 
could not eliminate. 
We give the results of our experiments in the form of Tables. 
Column I. gives the number of the experiment. 
Column II. gives the date. 
Columns III. and IV. state whether in the first and last period respectively the 
thermometer was falling or rising. 
Column V. gives the value of the equivalent calculated, the temperature scale being 
that of a mercury thermometer made of French hard glass. 
Columns VI. and VIL. give the same equivalent, reduced to the nitrogen and 
hydrogen scale of the Bureau International des Poids et Mesures. 
Column VIII. gives the temperature range of the experiment. 
