316 MR. BE. H. GRIFFITHS ON THE LATENT 
I have already remarked that I attach more value to Experiments VI. to XI. than 
to the preceding ones, and I shall therefore assume the mean value of L at 40°15 as 
572°60. | 
The close agreement between the means of Nos. XII. to XVI. and Nos. XVII. 
and XVIII. is very satisfactory when it is remembered that the rate of evaporation 
is in the last case nearly halved. 
I need searcely say that, had time permitted, I should have performed more experi- 
ments, especially at 30°. I do not, however, consider that the evidence would have 
been greatly strengthened. 
In the whole of the series from VI. onwards (v.e., after the adoption of the bent 
form of dropper) there is no experiment which gives results differing from the mean 
at that temperature by more than 1 in 1430, and in the groups at 30° the greatest 
divergence is 1 in 2900. The probable mean error of a small group of experimental 
results of this kind is therefore less than the probable error of some of the constants 
on which our conclusions are based, and a larger accumulation of such experimental 
numbers would not necessarily bring us any nearer to the absolute value. 
Conclusions. 
Temperature. Value of L 
Nitrogen thermometer. (in terms of thermal unit at 15° C.). 
AOSD. sy pont A ere aa ks Mee Meta Oe OO 
S000 Coo ik es oe te hk a aie aed OSLO 
Section XJ.—Driscussion OF THE RESULTS. 
From the conclusions arrived at in the last section we obtain (over the range 
30° to 40°15 C.) dL/dé = °6010. 
Suppose we assume with Reanavtt that L is a linear function of 0, it follows that 
wien! O-—==10 saa) 9 Gwe 
uO = 100% Wi 53663 
I admit the folly of attempting to extrapolate to such an extent where we have no 
evidence but that given by the experiments themselves. It is a different matter 
when we can bring forward independent evidence. 
In Section II. I dwelt upon the importance of the experiments of Dizrerict at low, 
and of REGNAULT at high temperatures ; the agreement between the values obtained 
by those observers and the ones resulting from the above extrapolation is so extra- 
ordinary that I give in detail their experimental numbers. 
As stated in Table I., ante, the mean value of all Diererici’s experiments was 
596°8 at 0°. He, however, regards certain of the experiments (whose results are 
given in his Tables II. and IV.) as of greater value than others, because the 
evaporating water was included in a platinum instead of a glass tube, and thus its 
