[ 553 3 
accurate Experiments and Reafonings of the learned 
Mr. Geoffrey , on a like Subftance made of Char- 
coal and an Alkali Salt 1 calcined together, in which 
he obferved all the Properties and Contents of Pot- 
ato above mentioned, particularly related in the 
Memoirs of the Royal Academy , for the Year 1717. 
This was made of the fame Materials, and had all 
the Properties above-related of our Pot-afh 5 particu- 
larly a green Lixivium , a ftrong fulphureous Smell 
and Tafte, a fulphureous green Precipitate, cryftal- 
lized Salts, and fulphureous Fumes with Oil of Vi- 
triol. From hence this learned Author concludes* 
that this Subftance contained the a&ive fulphureous 
Parts of the Wood, blended with more aftive igne- 
ous Particles. Thcfe, united with the alkaline Salts, 
make a kind of Soap, or fulphureous faponaceous 
Salt, refembling Soap of Tartar, or Htpar Sulphuris, 
The cryftallized Salts he attributes to the Acid of 
the Wood, mixing with the alkaline Salts. All 
thcfe Parts of the Wood then are contained in our 
Pot-afh; and he obferved the fame in the common 
Soda , or Qineres clavellati ; altho 5 they are in .a lefs 
Degree in that than in the Ruffian Pot-afh. 
ikftdes thefe, he toews that Pot-afh contains a 
metallic Subftance, which affords the Rruffian Blue. 
We may add further, that the Combination of thefe 
Principles makes many Properties in Pot-afh, more 
than what refult from them in a State of Separation. 
The rnoft remarkable of thefe feems to be. its explo-. 
f ve Quality 5 which we take to proceed from the 
cr} ftalhzed Salts approaching to the Nature of Nitre, 
and uniting with the Sulphur and Charcoal 5 by. 
which they form, from all thefe Ingredients of 
Gunpowder, 
