436 
0'-02, the light is of the usual violet colour, the fluorescence 
strong, and the spheric stratification the most distinct which 
I had seen with air. When the disc is positive, the form of 
the light is as in the preceding; when negative, there is a 
sheet of pink light on the mercury, and the bell is full of daz- 
zling blue, as fluorescent as the other. 
‘©18. Vapour of carburet of sulphur: a few drops are 
poured into the transfer jar, which is then filled with mercury, 
so as to displace all except the film which adheres to the jar. 
This, when the jar rises out of the hole, is vaporized: with 
water the quantity which thus adheres = ;; grain. In this 
case the tension of the vapour was about 0:15, as estimated 
by the height of mercury in the bell, compared with the gauge. 
The light was bright yellow green, the strata superb, but no 
exterior fluorescence. In ashort time it was decomposed, the 
bell being coated with sulphur, and the mercury with a red 
film, probably cinnabar. 
‘©19. Vapour of chloroform seems to conduct badly: the 
light is greenish, but with many branches; no fluorescence, 
and strata indistinct. The vapour was probably too dense. 
*¢20. A bit of phosphorus, carefully dried, was passed up 
into the transfer jar. At first the appearance was as in (16), 
but as the phosphorus evaporated, one of the hemisphere shells 
about 0:5 diameter became brilliant gold colour, and stretched 
itself up and down, while the others changed colour also, be- 
coming bluish-white. It then shrunk into a film, coating the 
disc, but retaining its peculiar splendour. Below them, for a 
third of the whole, there was a dark space, and orange light on 
the mercury; no fluorescence with quinine, and very little with 
platino-cyanide. Reversing current, the disc is orange, and 
the bell full of white light, which soon separates from the glass, 
forming a cone. Much phosphuret of mercury is formed. 
This is the most beautiful spectacle of all which I have seen. 
*¢21. Sulphurous acid gas: I had some trouble in filling 
these miniature jars (0'*1 diameter), but did so by means ob- 
