ig2 PHILOSOPHICAL TRANSACTIONS. [aNNO 1685. 



jilicant Soda. — In this salt I could see some particles, flat, thin, 4-sided, and 

 6-sided figures, as N° l6, fig. A and B. Also oblong figures, as C, whose 

 sides run up sharp : these salts were dissolved by the least moisture of the air. 



Sal Ammoniac. — The figure of this salt dissolved in water generally appeared 

 like the boughs of a tree, beset with irregular leaves, one larger than another, 

 as is represented N° 17, fig. AE. In another place lay 5 or 6 branches like A, 

 seeming to proceed from a common centre, as E. I saw also salt particles like 

 B and C ; and where there were no branches, the scattered salts looked like 

 so many flints, differing from each other in size, but being never perfectly 

 round, as fig. D. 



Experiments at Woolwich, March 18, l651, for trying the Force of Great Guns. 

 By Mr. Greaves.* N° 173, p. lOQO. 



At 200 yards distance from the platform for the great ordnance there were 

 raised 3 butts, one behind another: the space between the 1st and the 2d 

 butt was 14 yards, between the 2d and the 3d, 8. The thickness of each butt 

 was 19 inches, whereof 13 was of beams of massy oak fastened into the ground, 

 and set so close that they touched each other: on each side were planks of oak, 

 each 3 inches thick, which were joined close, and fastened on both sides with 

 iron bolts, and strong pins of wood ; and on the back at the ends, and on the 

 middle there were 3 braces of elm, 12 inches broad, and 5 inches thick. 



The first experiment was with an iron demy cannon of SSOOlb. weight, with 

 a cylindrical bore ; the powder 1 Olb., the bullet 32lb. of iron, which pierced 

 through the first two butts, and stuck in the 3d, so as the ball was almost quite 

 within, but the timber not shivered, nor scarcely split. The like effect happened 

 with Qlb. and Bib. of power. — ^The 2d experiment was with an iron demy 

 cannon having a taper bore, and being 36oolb. in weight, and 4 inches longer 

 than the former ; the powder 7lb. the iron bullet 32lb. and which in 3 trials 

 seemed to have the same force with the first. One of the shots piercing 

 through the 2d butt, and lodging near the edge of the middle butt of elm, tore 

 it, but by the yielding of it, the bullet glanced aside off the 3d butt, and 



' * This was probably Mr. John Greaves, a good mathematician and antiquary. After leaving the 

 university (Oxford), he was sometime professor of geometry in Gresham College. He afterwards 

 visited several foreign parts, as Holland, France, Italy, Turkey, Egypt, &c. returning home well 

 stored with manuscripts, gems, coins, and other antiquities. After his return he was appointed pro- 

 fessor of astronomy at Oxford, but he was obliged to resign that professorship by the persecution of 

 the parliamentary visitors. Mr. Greaves was born at Colemore in Hampshire, in l602 ; and he died 

 in 1652. He was the author of several learned works; as the Egyptian pyramids, the ancient 

 weights and measures, and other antiquarian subjects. 



