440 Mr. Tomlinson, on Colours, fyc. [Junk 



With muriate of lime the same result was obtained with 

 this addition ; on looking steadfastly into the glass with one 

 eye, the other being closed, a variety of white spots began 

 to form on the iris, giving the eye an unpleasant mouldy 

 sort of appearance. The aqueous humour seemed to con- 

 sist of one isolated drop of water, so distinct from any other 

 part of the eye, that it seemed as if it would have dropped 

 down into the glass ; in a short time the transparent mem- 

 brane covering the pupil became milky, and the glass and 

 fluids indistinct. I have repeated this experiment with the 

 same results, except that the white spots on the iris were 

 not so numerous. 



With a deep blue solution on mercury obtained by indigo 

 in sulphuric acid, the accidental orange-yellow was obtained. 



These accidental colours are neither modified nor changed 

 by the reflection of various coloured solids, such as blue, 

 yellow and green balls, &c, the accidental colour belong- 

 ing to the upper fluid and not to the object reflected. In 

 order to obtain them, however, two liquids of different den- 

 sities must be employed in order to obtain two reflections, 

 and for the lower fluid nothing is so convenient as mercury. 

 Indeed, I have not as yet met with any other fluid that at 

 all answers the purpose. 



The effect is very beautiful with litmus solution and mer- 

 cury when the flame of a candle is employed ; the two re- 

 flections have the appearance of hollow cones placed above 

 and within each other, the lower flame being the accident. 



With muriate of lime the lower flame reflected by the 

 mercury was of a decided yellow, but the accidental colour 

 of a very faint blue ; whereas, by natural light the acci- 

 dental is of a fine indigo. 



The green flame obtained by boracic acid in alcohol pre- 

 sents a very fine appearance with litmus and mercury. A 

 watch glass should be employed supported on a ring formed 

 out of a piece of wire, and other lights in the room extin- 

 guished. 



Yours, Dear Sir, 

 very sincerely, 



CHARLES TOMLINSON. 



Brown Street, Salisbury, 

 April 22, 1835. 



