786 



PHILOSOPHICAL TRANSACTIONS. 



[anno 1800. 



Transmission. 

 Empty tube and two glasses .796 



Well-water and ditto 789 



Sea-water 712 



Liquids. 



Stoppage. Transmission. 



. 204 Spirit of wine and 2 glasses .776 



, 211 Gin 374 



. 288 Brandy 00381 



Scattering Transmissions. 



Transmission. 

 Crown glass, one side 1 . . ^ 



rubbed on emery. $ 



Coach glass, ditto 115 



Crown glass, both sides ^ g R * 



rubbed on emery. J 



Coach glass, ditto 0542 



The two first, together .. .03158 . 

 The two next, together . . .0208 



Stoppage. 



854 



885 



932 



9*6 

 969 

 979 



Transmission 

 The four first, together . . .00456 

 Olive colour, burnt in glass .0160 



Calcined talc 00345 



White paper 00556 



Linen Oi83 



White Persian 0841 



Black muslin .263 



Stoppage. 

 . 224 

 . 626 

 • 996 



Stoppage. 

 995 

 984 

 997 

 99* 

 952 

 916 

 737 



Table of the Proportional Terrestrial Light Scattered by various Substances. 



The same apparatus which has been used to gain the results of the preceding 

 table, has also been employed for the following one, with no other difference than 

 that while the vane with the white paper remained on one side, the other vane was 

 successively covered by the objects whose power of scattering light was to be ascer- 

 tained, and both vanes were viewed directly through the 2 open holes in the screen ; 

 the eye being stationed in the same place as before. It will be found, that this table 

 contains the scattering of more objects than have been referred to in the preceding 

 paper; but, as I made these experiments in a certain order, I thought it would be 

 acceptable to give the table at full length. The 1 st column gives the names of the 

 objects ; and the 2d contains the number of rays of light scattered by them, when 

 compared to a standard of white paper, which is supposed to scatter IOOO. 



table 8. 



Rays of light. 



White paper scatters 1000 



Message card 1 000 



White linen 1008 



White cotton 1054 



White chamois leather, smooth side . . 1228 



White worsted 620 



White Persian, suspended 67 1 



White Persian, on whitish-brown paper 719 



White Persian, on white Persian 818 



White muslin 827 



Red paper 158 



Deep pink-coloured paper 513 



Pale pink- coloured paper 62 1 



Orange paper 619 



Yellow papei 824 



Pale-green paper 549 



Dark-green paper ; 308 



Rays of light. 



Pale-blue paper 665 



Dark-blue paper 1 49 



Indigo paper, with a strong gloss .... 144 



Dark-violet paper scatters 75 



Brown paper ] 01 



Black paper, with a strong gloss 420 



Black satin. . . 102 



Black muslin, suspended 64 



Black muslin, upon black muslin .... 18 



Black worsted 16 



Black velvet . , 7 



Tin-foil 8483 



Iron 10014 



Copper 13128 



Brass 43858 



Gold-leaf paper 124371 



I cannot help remarking, that in making these last experiments, I found that 

 black paper could not be distinguished from white ; and that, on bringing it a little 



