28
M, MELLONI ON THE FREE TRANSMISSION
the heat, the lamp was brought nearer and nearer until we obtained, through the combination of the three plates, the same indication of 19° that was furnished by the thick glass when exposed singly to the radiation of 30°.
| Table I.—Glass (uncoloured). Common thickness 1ᵐᵐ·88. | ||
| Deviations of the galvanometer. |
Rays transmitted. | |
| ° | ||
| No screen | 30·00 | 100 |
| Flint-glass (of Guinand) | 22·90 | 67 |
| Flint-glass (English) | 22·43 | 65 |
| Flint-glass (French) | 22·36 | 64 |
| Another kind | 22·19 | 64 |
| Mirror-glass | 21·89 | 62 |
| Another kind | 21·10 | 60 |
| Another kind | 20·78 | 59 |
| Crown-glass (French) | 20·58 | 58 |
| Window-glass (common) | 19·25 | 54 |
| Another kind | 18·56 | 52 |
| Another kind | 17·83 | 50 |
| Crown-glass (English) | 17·22 | 49 |
| Table II.—Liquids. Common thickness 9ᵐᵐ·21. | ||
| Deviations of the galvanometer, |
Rays transmitted. | |
| ° | ||
| Mirror-glass | 19·10 | 53 |
| Carburet of sulphur (colourless) | 21·96 | 63 |
| Chloride of sulphur (of a strong brownish red colour) | 21·83 | 63 |
| Protochloride of phosphorus (colourless) | 21·80 | 62 |
| Hydrocarburet of chlorine (colourless) | 13·27 | 37 |
| Nut-oil (yellow) | 11·10 | 31 |
| Essence of turpentine (colourless) | 10·83 | 31 |
| Essence of rosemary (colourless) | 10·46 | 30 |
| Oil of colza (yellow) | 10·38 | 30 |
| Oil of olives (greenish yellow) | 10·35 | 30 |
| Naphtha (natural—a light brown yellow) | 9·77 | 28 |
| Balsam of copaiba (a sufficiently decided brown yellow) | 9·39 | 26 |
| Essence of lavender (colourless) | 9·28 | 26 |
| Oil of pink [huile d'œillet] (very slightly yellowish) | 9·26 | 26 |
| Naphtha (rectified, colourless) | 9·10 | 26 |
| Sulphuric æther (colourless) | 7·59 | 21 |
| Pure sulphuric acid (colourless) | 6·15 | 17 |
| Sulphuric acid (of Nordhausen, of a sufficiently decided brown) | 6·09 | 17 |
| Hydrate of ammonia (colourless) | 5·47 | 15 |
