Paper, 'On the specific heats of minerals' by John Joly

Description

Joly writes: 'A number of experiments were made on minerals by the method of condensation, using the form of gravimetric calorimeter described in the beginning of the paper on calorimetry. The condensation of steam being in all cases employed, the values recorded are the mean specific heats between atmospheric temperatures approximating to 12° C., and steam temperature, about 100° C. More exactly, the values recorded are the mean calorific capacities for a rise of one degree between the limits t1 and t2, tabulated in each case. The specimens dealt with were chosen as good samples of the mineral free from visible impurities. But before detailing the particulars of the experiments a few notes on the discriminative value and physical interest attached to this application of calorimetry may not be amiss. It seems probable that the neglect of the use of the specific heat constant is to be ascribed to the difficulties besetting its determination. Certainly if its determination was as easily effected as we effect the determination of the specific gravity of a body, there are on the other hand sufficient reasons to recommend its use as in general of more physical value and interest than the much used specific gravity. There are cases indeed where specific gravity, as it is possible to obtain it, is misleading, and where specific heat gives at once valuable information on the probable chemical nature of the substance. Such eases would arise with bodies of loose vesicular or hollow structure. No misleading variations need be introduced into the thermal constant by mere conditions of volume.'

Annotations in pencil and ink throughout.

Subject: Chemistry / Physics

Received 28 June 1886. Read 18 November 1886. Communicated by George Francis Fitzgerald.

A version of this paper was published in volume 41 of the Proceedings of the Royal Society as 'On the specific heats of minerals'.

Reference number

PP/9/6

Earliest possible date

1886

Physical description

Ink and graphite pencil on paper

Page extent

22 pages

Format

Manuscript