GENERAL INDEX. 39 



Sounds, transmission of * PNEUMATICS , . 29 



Spanish Burtons, pulleys ...... MECHANICS,^ ii. 36 



Spar, Iceland, (or calcareous) its composition, &c. , . POLAR. OF LUJHT , 1 



multiplication of images in . , . 61 



influence of heat on . , , , 63 



Species (of double refraction, new) in Analcime . . . 39 



Specific caloric, observations on . . . . HEAT . . 33 



. . " gravity HYDROSTATICS . 13 



tables of in different bodies .... 19 21 



heats of various metals ascertained .... HEAT , 39 



Spectra, ocular, or accidental colours, accounted for , . OPTICS . 46 



in crystals of Rochelle salt . . . . POLAR. OF LIGHT . 33 



Spectrum, prismatic, described . . . . OPTICS . . .23 



de-oxydizing power of . . . 29 



.. heating power of . , . . . . 



, . illuminating power of . . 29 



lines crossing it accounted for , . , , .30 



table of temperature of its rays . . , 29 



Sphere of glass, refraction of light through ... ... 9 



Spheres and spheroids of glass, of the double refracting force in . POLAR. OF LIGHT . 51 



Spherical aberration of light in lenses .... OPTICS . . 20 



in mirrors . , . . . 22 



Spiral spring in watch-work, a mechanical power . . MECHANICS, t. ii. . 26 



Spirit-level, description of -..... HYDROSTATICS . 10 



Spirit of wine, manufacture of . HEAT . . .56 



Splendour of coloured rings as seen in topaz . . . , POLAR. OF Lie HT . 23 



Spouting fluids, laws of ...... HYDRAULICS . . 4 



Springs, spiral, in watch-work, power of . , . . MECHANICS, t. ii. . 26 



intermitting and reciprocating cause of . . . HYDROSTATICS . 21 



curious one in Devonshire . . . . . 22 



Spur-wheel, form and application of . . , . , MECHANICS, t. ii. . 30 



Squinting, cause of ........ OPTICS . . 45 



Stars, fixed, their immense number ..... PRELIMINARY TREAT. 15 



State of light partially polarised by reflection . . . POLAR. OF LIGHT . 12 



Statics, definition of . MECHANICS, t. L 1 



Steam-boat wheels, observations on . HYDRAULICS . . 24 



experiments on .. HEAT . 4 39 



engine, history of ....... MECHANICS, t. i. . 32 



economical uses of ..... t HEAT . t 52 



engine, Watt's improvements on .... . , .46 



.. high and low pressure .... MECHANICS, t i. . 32 



. . Marquis of Worcester ..... . 32 



Newcomen's and Savery's . . , 



Steel-yard mode of graduating . 1. ii. 18 



Still, different forms of , HEAT . . 57 



Straps, combination of, with wheels and axles * . . MECHANICS, t. ii. , 27 



Stream, how to measure the velocity on . . . 1. i. , 22 



wheels, observations on . . , , , HYDRAULICS . .23 



Strength, animal, computation of . . , . MECHANICS, t i. . 27 



experiments and calculations on . . , 28 



human, compared with that of the horse . . , 29 



Structure of mother of pearl ...... OPTICS . . .39 



of composite doubly refracting crystals . . POLAR, of LIGHT . 56 



of the Brazilian topaz .... . . . 57 



. . of sulphate of potash ..... \ 57 



doubly refracting, communicated to glass . . . 52 



of the perfectly-formed amethyst .... . 43 



Successive reflexions, polarisation of light by ... ____________ < ] j 



Suc f >on pipe and pump, described ...... PNEUMATICS , 21 



.> hate of lime, influence of heat upon .... POLAR. OF LIGHT . 63 



ish and copper, curious experiment with . . . . 63 



Sun i. Watt's, described .... MECHANICS, t. ii. . 63 



. separated HEAT . . 28 



risation of light at the . , . POLAR. OF LIGHT 10, 11 



a balance . . . MECHANICS, t. ii. . 14 



t of its nest ... . PRELIMINARY TREAT. 32 



. . HYDROST. 2. PNEUM. 26 



. PNEUMATICS , . ,27 



