rOL. XV.] PHILOSOPHICAL TRANSACTIONS. ISQ 



and thickness equal, and less than their length, as fig.B, N°8. Many of them, 

 though they had 6 sides, were somewhat irregular; some shaped like the flint 

 of a firelock, as fig. D; and though most of them were irregular, yet I judged 

 if they had not lain too close together, their form would have been like those 

 of fig. A; for when the parts of the camphor at first were small, and lay too 

 close together, they might take from one another the means of increasing re- 

 gularly every way ; but when the parts are great, and come to apply their sides 

 to one another, they then make very large and irregular salts. 



Salt of the Ashes out of an Oven* for the Foundery of Cannon, — I mixed some of 

 this with water, and let it stand till the grosser parts subsided, and the liquor 

 was pretty clear, and then there appeared a very great number of small clear 

 thin pipes, so extremely slender, that I could hardly see them ; when these 

 pipes were increased to about the size of the 25 th part of a hair, their ends 

 were sloped, as N° 9, fig. A. Of these salts there were several thousands in one 

 drop of water. There were likewise floating about a kw particles like fig. B ; 

 and though I could not discern the thickness in the first figures, yet in these 

 last it was very plain, and small in comparison of the breadth : at another time 

 there appeared salts like fig. C. 



Salt, or Ashes of a Tin or Lead Oven.* — Our Porcelain bakers use much tin 

 or lead, which they calcine in their ovens. This work is so prejudicial to those 

 that tend it, that a man is unable to stand before the mouth of the oven more 

 than 24 hours at a time, and then he looks as if he were poisoned : so that 

 every day a fresh man is employed to take care of the oven, and remove the 

 scum from the surface of the lead. Hence I was induced to examine some of 

 that greyish substance which sticks to the stones, on which the flame of the 

 oven beats. Having dissolved it in water, and let it stand to settle, I found 

 several oblong figures, as N° 10, fig. A: they were of different magnitudes, 

 and some larger than fig. B; some were sharp at both ends, as fig. C. All 

 these were generally without any discernible thickness, and were as transparent 

 as the clearest water. I particularly observed that three figures, two of C and 

 one of B, lay in a quantity of water not so large as a sand: while I caused some 

 heat in this water, and continued to watch it, imagining the other salts it con- 

 tained would increase the bulk of these three, I could find nothing but very 

 small square salts, whose sides rose up pyramidally; these indeed grew larger, 

 but the others were not altered : as the square salts grew larger, they became 

 so much the more irregular, because the smaller salts were driven upon them 

 or as it were attracted; for as they came near them, the foremost had as quick 



* Furnace. 



