1814.] macie during the Year 1813. 11 



White wax 7-2108 lbs. troy 



Olive oil (i-SDOO 



Oil of colza 7'0.')0G 



- Alcohol 5-1400 



Sulphuric ether G'1178 



Napluh;i 5-5900 



Tallow 6-5755 



He has determined also the quantity of heat evolved by the com- 

 bustion of the ditlcrcnt woods; from which it appears that the 

 lime-tree gives out the most heat, and the oak the least, during 

 combustion. 



2. Delaroche ancl Berard have made a very complete set of 

 experiments to determine the specific heat of the dirterent gases. 

 The following table exhibits the results which they have obtained: 



Si)cclfic heat of Water 1-0000 



Common air 0-2669 



Hydrogen gas 3-2936 



Carbonic acid gas 0-2210 



Oxygen gas 0-2361 



Azotic gas 0-2754 



Nitrous oxide gas 0*2369 



Oleliantgas 0-4 207 



Carbonic oxide gas 0-2884 



Aqueous vapour 0-84/0 



3. Mr. Sharpe has shown that the density of steam Increases 

 with the temperature at which it is evolved. This accounts for the 

 increase of its elasticity without its being necessary to conceive any 

 alteration in its latent heat. It follows from this that the specific 

 gravity of steam is proportional to its elasticity, or to the tempera- 

 ture at which it is evolved. 



At 32° Its specific gravity is 0-0046 



212 0-6896 



252 l-;'.792 



307 2-7584 



4. Dr. Delaroche has made some important additions to the 

 doctrine of radiant heat as explained by Mr. Leslie. These addi- 

 tions may be comprehended under the following |)ropositK)ns : — 



First Proposition. — Invisible radiant heat may in some tircum- 

 stanees pass directly through glass. 



Second Pro/jositiofi. — The quantity of radiant heat which passes 

 directly through glass is «;o much greater, relative to the whole heat 

 emitted in the same direction, as the temperature of the source of 

 heat is more elevated. 



'J'/iird Pro/iosilioii. — The calorific rays, wliicli have already 

 pjissed through a screen of glass, experience in passing through a' 



