4 3 REPoRtT—1840. 
of thickness. Different numbers of glass screens were also em- 
ployed in combination ; the same conclusion also held good. 
The results with a numerous series of screens of various me- 
dia, solid and liquid, were then tried, and are stated in a series 
of tables :— 
Table I. Various kinds of uncoloured glass. 
Table II. Liquids: to give a general sketch, the order of 
transmission was as follows, beginning with the greatest :— 
Carburet of silver. 
Chlorides. 
Oils. 
Acids. 
Water. 
Table III. Crystallized bodies, transparent and opake; the 
results follow no relation to transparency: the following is the 
general order :— 
Rock salt. 
Various crystals. 
Alum. 
Sulphate of copper—no effect. 
Table IV. Coloured glasses. Red and violet transmitted 
most—yellow, green and blue, least—heat. 
The author concludes, in general (the source being a lamp), 
that the diathermancy is not proportional to the transparency ; 
and makes some general remarks on these results as related to 
those of Seebeck on prismatic dispersion. 
A supplement to the last paper was presented by the same 
author to the Academy, April 21, 1834, entitled ‘ New Re- 
searches on the immediate Transmission of Radiant Heat 
through different Solid and Liquid Bodies.”’ It is published in 
the Ann. de Chimie, lv. 337, and translated in Taylor’s Scien- 
tific Memoirs, Part I., p. 39. 
The author first investigates ‘‘the modifications which calo- 
rific transmission undergoes in consequence of the radiating 
source being changed.”’ 
He employs four sources of heat. 1. A Locatellilamp. 2. 
Incandescent platina. 3. Copper heated by flame to about 730° 
Fahrenheit. 4. Hot water in a blackened copper vessel. The 
heat from each of these sources was first compared as transmit- 
ted through plates of glass of different thicknesses, from *07 
millims. to 8 millims. The results are given in a table, from 
which it appears that with copper and hot water the diminution 
of effect is rapid, with an increase of thickness in the screen; with 
water it is nothing beyond a thickness of 5 mm. A second ta- 
ble gives results for about 40 solid media of different kinds, of 
