ELECTRICAL STANDARDS. 157 
important thing is that the same conception should be adopted everywhere, 
and for this reason I will fully accept the decision of the majority of the 
Committee. 
8.—From Dr. K. Olszewski, Professor of Chemistry, Cracow, 
December 14, 1895. 
Ihave taken the advice of my colleagues in the Cracow University, 
Professors Witkowski and Natanson, and I beg to submit to your attention, 
as well as to that of the British Association Electrical Standards Com- 
mittee, the following suggestions, being the conclusions arrived at con- 
jointly by the above-named gentlemen and myself. 
1. It would be advisable, on theoretical grounds, to select a Joule, or 
107 ergs, as the fundamental theoretical or ideal unit of heat-energy. 
Hence the following proposal is brought forward :— 
‘That the theoretical or thermo-dynamical, or, say, c.g.s. standard 
thermal unit, be defined as the heat equivalent of a Joule or of 107 
ergs, and termed a thermal Joule.’ 
2. That, as a practical thermal wnit, the quantity of heat required to 
raise | gramme of pure water through 1° of the thermo-dynamical scale at 
15° of that scale be temporarily adopted. 
8. That, in view of the exceptional importance of the question, steps be 
taken, by international co-operation or otherwise, leading to the deter- 
mination of the numerical value of the ratio between the theoretical unit 
and the practical unit, defined by 15°, as above stated, by some at least of 
the leading physical and metrological laboratories and institutions of the 
world, with the highest degree of accuracy nowadays attainable ; and to 
the extension (if possible) of such determinations over as great a range of 
temperature as practicable. Added to the highly valuable work already 
done, such an investigation cannot fail to settle the question of the specific 
heat of water ; and if this be done, the subject of thermal units will have 
lost nearly all of its present difficulty. 
9.—From Dr. Chappuis, Bureau International des Poids et Mesures, 
Sevres, February 2, 1896. 
[TRANSLATION. ] 
. . . Your arguments have led me to accept the propositions given by 
you on pp. 452 and 453. 
If, however, I may. be allowed to express a wish, it is that the values 
may be reduced to the normal scale of temperature, 7z.e., to that of the 
hydrogen thermometer, and not to the air or nitrogen. 
It is true that the difference between these scales is very small, but 
still it is perfectly measurable. Some experiments of the Bureau Inter- 
national des Poids et Mesures (not yet published) have led me to the 
conclusion that the thermometric scale of hydrogen is independent of the 
initial pressure between 0:5 and 2 atmospheres, and that the hydrogen 
thermometer at constant pressure gives sensibly the same values as the 
thermometer at constant volume. It is not so with the nitrogen or the 
air thermometer. 
The difference between the nitrogen and hydrogen scales is indicated 
both in the original memoir (‘Trav. et Mém. du Bureau International,’ 
