263- On the Defmile Proportions m which the [April, 



The mucous matter remaining on the filter had some resemblance 

 to oxide of tin. When dried in a vacuum it was semi-transparent, 

 and greyish coloured. When heated to 212'' in a vacuum, it gave 

 out water, and became yellow. This yellow matter when exposed 

 to the direct rays of the sun, is decomposed in a few minutes. It 

 becomes at first green, and then grey. Decomposed by combus- 

 tion it gave 63-529 per cent, of oxide of lead. Hence it wa-f 

 composed of 



Sugar of milk 36-471 100-00 



Oxide of lead 63-529 174-15 



100-000 



Tliese 174-15 of oxide of lead contain 12-45 of oxygen ; but 

 we have seen that sugar of milk contains 12i water, or 100 sugar 

 of milk are combined with 14 water, in which there are 12-245 of 

 oxygen. It is therefore clear that in the saccolactate of lead ana- 

 lyzed, the sugar of milk ouglit to contain four times as much 

 oxygen as the oxide of lead. 



A part of the filtered liquid mixed with caustic ammonia, depo- 

 sited an abundant precipitate, possessing all the characters of the 

 above-described saccolate, except the mucous aspect and the pel- 

 lucidity after desiccation. It became equally yellow when the 

 water of combination was driven off. Analyzed by combustiorr 

 it gave 64-14 {■)er cent, of oxide of lead. Treated by neutral acetate 

 of lead it gave a little carbonate of lead, to the presence of which 

 it probably owes its difference from the saccolate above described. 



Another part of the liquid evaporated to dryness gave a gummy 

 and transparent mass, which did not attract moisture from the 

 atmosphere. When dried at 212° in a vacuum, it swells up, be- 

 comes frothy, and acquires a yellow colour. Analyzed by com- 

 bustion it left 18-123 per cent, of oxide of lead. I consider this 

 substance as a super-saccolate of lead. It is composed of 



Sugar of milk 81-877 100 



Oxide of lead 18-123 22-1 



Thus it appears that in the super-saccolate the sugar of milk is 

 combined with -|- of the quantity of base as in the neutral saccolate. 



For Lilll^ = 21 •77' The error in the result is owing to the im- 



o 



possibility of drying tiie gummy combination without exposing it to 

 a temperature at which it begins to undergo decomposition to which 

 its yellow colour is owing. 



Oxide of lead digested with sugar of milk appears at first not in 

 the least altered. It is, however, converted into a subsaccolate of 

 lead. When well washed, and dried in a vacuum in the tem- 

 perature of 212°, it forms a yellow powder. When analyzed by 

 combustion it leaves 87-2 per cent of oxide of lead. Hence it is 

 composed of 



