152 ON THE WORKS AND CHARACTER 



No. 3926. Black lead pencil bought at Frankfort. May, 

 1805. 



1. It cost thirty-six kreutzers, or about one shilling and two pence, Eng- 

 lish. 



2. Held in the candle the point does not soften or seem affected. 



3. A bit heated at the blow-pipe in the spoon emits a copious white smoke 

 without any sensible smell of sulphur, and the smoke settled as a white 

 powder on bodies. The bit of pencil falls into a coarse scaly powder. This 

 powder looked so like the scaly manganese or iron I suspected its being 

 such ; but melted with saltpetre it consumed and did not impart to it the 

 least bit of green. 



A bit of the pencil heated with carbonate of soda did not form visible 

 liver of sulphur, but the solution of the mass stained silver. 



No. 3926. Factitious pencil bought at Frankfort in 1805. 



1. A bit exposed at the blow-pipe burns with a flame and emits a copious 

 white smoke. A matter remains which falls to powder under the touch 

 and seems to be plumbago. 



No. 5763. Perhaps Fluorspar, from a lead mine, Matlock 

 bath, in Derbyshire, 1799. 



1. Powdered, and put into muriatic acid, there is a momentary efferves- 

 cence from some particles of carbonate of lime but no sensible diminution 

 of the powder. 



2. Heated in sulphuric acid on a bit of glass it effervesced much, but the 

 glass was not depolished. 



3. Sulphate of soda formed hydrated sulphate of lime in the solution 

 No. 1. 



4. It melted with carbonate of soda, with effervescence, and formed a 

 transparent glass, with opaque white quartz in it which more alkali did not 

 dissolve. 



5. This stone scratches glass. 



6. The glass (4) was treated with muriatic acid ; the whole did not dis- 

 solve. 



7. This muriatic solution exhaled dry, left no crystals on adding water. 

 On drying again, and heating more, and adding a small quantity, a dark 

 matter, probably oxide of manganese, was left. 



Sulphuric acid added to this solution formed no immediate precipitate, 

 but one of hydrated sulphate of lime formed. 



These minute experiments are recorded for a considerable 

 number of specimens. It may be that there were many 

 more of them than have been preserved. They show with 

 what careful and minute accuracy Smithson worked and 

 noted all he did. A large number of these notes were of 

 rocks and clays. This seems to have been the only way in 

 which he busied himself with geology. 



A system of chemical nomenclature was made use of in 

 these jottings which, perhaps, deserves notice on account 

 of its curiousness. It is an extension of the astronomical 

 signs, as applied to certain of the metals. They are as fol- 

 lows : 



