| The refracting Bodies. | The Proportion of the Sines of Incidence and Refraction of yellow Light. | The Square of BR, to which the refracting force of the Body is proportionate. | The density and specifick gravity of the Body. | The refractive Power of the Body in respect of its density. |
|---|---|---|---|---|
| A Pseudo-Topazius, being a natural, pellucid, brittle, hairy Stone, of a yellow Colour. | 23 to 14 | 1'699 | 4'27 | 3979 |
| Air. | 3201 to 3200 | 0'000625 | 0'0012 | 5208 |
| Glass of Antimony. | 17 to 9 | 2'568 | 5'28 | 4864 |
| A Selenitis. | 61 to 41 | 1'213 | 2'252 | 5386 |
| Glass vulgar. | 31 to 20 | 1'4025 | 2'58 | 5436 |
| Crystal of the Rock. | 25 to 16 | 1'445 | 2'65 | 5450 |
| Island Crystal. | 5 to 3 | 1'778 | 2'72 | 6536 |
| Sal Gemmæ. | 17 to 11 | 1'388 | 2'143 | 6477 |
| Alume. | 35 to 24 | 1'1267 | 1'714 | 6570 |
| Borax. | 22 to 15 | 1'1511 | 1'714 | 6716 |
| Niter. | 32 to 21 | 1'345 | 1'9 | 7079 |
| Dantzick Vitriol. | 303 to 200 | 1'295 | 1'715 | 7551 |
| Oil of Vitriol. | 10 to 7 | 1'041 | 1'7 | 6124 |
| Rain Water. | 529 to 396 | 0'7845 | 1' | 7845 |
| Gum Arabick. | 31 to 21 | 1'179 | 1'375 | 8574 |
| Spirit of Wine well rectified. | 100 to 73 | 0'8765 | 0'866 | 10121 |
| Camphire. | 3 to 2 | 1'25 | 0'996 | 12551 |
| Oil Olive. | 22 to 15 | 1'1511 | 0'913 | 12607 |
| Linseed Oil. | 40 to 27 | 1'1948 | 0'932 | 12819 |
| Spirit of Turpentine. | 25 to 17 | 1'1626 | 0'874 | 13222 |
| Amber. | 14 to 9 | 1'42 | 1'04 | 13654 |
| A Diamond. | 100 to 41 | 4'949 | 3'4 | 14556 |
The Refraction of the Air in this Table is determin'd by that of the Atmosphere observed by Astronomers. For, if Light pass through many refracting Substances or Mediums gradually denser and denser, and terminated with parallel Surfaces, the Sum of all the Refractions will be equal to the single Refraction which it would have suffer'd in passing immediately out of the first Medium into the last. And this holds true,