1819.] Mr, Watson's Experiment with, the Solar Microscope. 429 



to the shutter in the usual manner, but omitting to screw on the 

 Wilson's microscope. Instead also of placing the white paper 

 screen opposite to the window, it must be placed sideways on 

 the right hand side of the window. Now take the long piece of 

 mahogany with the prism at one end, and place the tubes with 

 their stand upon the other end. This apparatus is to be sup- 

 ported on a table close to the window in such a manner that the 

 middle of the prism may be within a few inches of the end of 

 the microscope, and the tubes within about 12 inches of the 

 paper screen. The sun's rays on being admitted into the room 

 will strike on the prism, and be divided. By a slight motion of 

 the apparatus, the coloured rays may easily be made to fall on 

 the inner surface of one of the tin tubes, from whence they wilt 

 be reflected, and then refracted by the two convex glasses ; after 

 which, the picture already described, will make its appearance 

 upon the screen. 



The cloudy appearance arises from inequalities in the reflect- 

 ing surface of the tin. This effect may be increased by making 

 a few small indentations on the inner surface of the tubes. 

 When the clouds are well defined on the screen, and the colours 

 bright, then the apparatus is rightly adjusted. By altering the 

 position of the tubes, or by using one, instead of both, some very 

 pleasing changes will be produced. 



I have been thus particular, in order that the operator may not' 

 fail to succeed. Perhaps this experiment will serve as a good 

 illustration of that splendid display of nature's colouring which 

 we sometimes witness about the time of sun-set, when the 

 " shifting clouds in all their pomp attend his setting throne." 

 1 am, Sir, your most obedient servant, 



James Watson. 



Article V. 



Population of Bombay.* By Sir James Macintosh, M. P. 



The public has hitherto received little authentic information 

 respecting the population of tropical countries. The following 

 documents may, therefore, be acceptable, as contributions 

 towards our scanty stock of knowledge on a subject which is 

 curious and not unimportant. 



No. I. is an account of the deaths in the island of Bombay 

 from the year 18U1 to the year 1808 inclusive, founded on 

 returns made to the police office of the number of bodies buried 

 or burned in the island. These returns being made by native 

 officers, subject to no very efficient check, may be considered as 



• From the Transactions of the Literary Society of Bombay. 



