of Edinburgh, Session 1870-71. 
321 
5. Note on an Ice Calorimeter. By Dr A. Crum Brown. 
The principal upon which this calorimeter is founded is, that a 
contraction of a definite amount takes place on the conversion of 
ice at 0° C. into water at 0° C., and that a definite amount of heat 
is required for this conversion. Early in the year 1866 I sent a 
description and drawing of the instrument to Messrs Kemp & Co., 
instrument-makers here, with an order to have it constructed. 
Some mechanical difficulties occurred which prevented its comple- 
tion at the time. I should not have laid before the Society an 
account of an unfinished instrument were it not that Professor 
Bunsen has recently published * an account of a calorimeter 
founded on the same principle. The two instruments are quite 
different in detail, and are primarily intended for different pur- 
poses — Professor Bunsen’s for the estimation of specific heat, and 
mine for the estimation of the heat produced during chemical 
changes. 
While, of course, fully acknowledging Professor Bunsen’s priority, 
I lay this note before the Society for the purpose of preserving to 
myself the right to use my own instrument. 
It consists of a cylindrical vessel A, the calorimeter , furnished 
with a tightly-fighting flanged lid of a conical form. This is fixed 
to the corresponding flange on the calorimeter by means of binding 
screws, and has a small hole at its apex, which can be completely 
closed by means of a screw D. 
Within the calorimeter is contained a smaller cylindrical vessel 
B, the laboratory , closed above by means of a flanged lid. Into it 
open two tubes, EE and FE. One of these, EE, carries a small 
plate, upon which apparatus may be placed. From the bottom of 
the laboratory a tube, GGrGf, passes, spirally bent in its descending 
part, and having a reservoir with a stop-cock between its descend- 
ing and ascending parts. All these tubes pass tightly through the 
lid of the calorimeter. 
The whole apparatus is enclosed in an outer cylinder CO. 
The doubly bent glass tube II connects the vessel K within the 
calorimeter, and the vessel J without. It passes through a tight 
stuffing-box in the wall of the calorimeter, and through a perforated 
* Poggendorff’s AnnaleD, vol. cxli. p. 1. 1870. 
