1822] Pirotechnia of Venoceio Biringuccio Siennese. 367 
rali,” that arsenic is mixed with almost all metallic ores, and the 
opinion that in volatilizing it carries off whatever silver they 
may contain. C. Della Giallamina, Zaffara, et Manganese. 
This chapter contains the earliest mention with which I am 
acquainted of manganese. Its use, both in tinging porcelain 
and glass, and in rendering the latter colourless, is noticed. 
The chapters on gems and glass contain little of interest. Those 
on the assay and reduction of metals are entirely practical, and 
show an intimate acquaintance with the detail of all the pro- 
cesses then inuse. In treating of alloys, he mentions the supe- 
riority of English tin. 
The alloy for bell metal he states to contain from 22 to 26 
per cent. of tin; that for other purposes of casting from 8 to 12. 
Enters largely into detail on the casting both of artillery and 
bells. At p. 100, he mentions a singular mode of soldering large 
bells when damaged, by carrying the curved chimney of a fur- 
nace constructed for the purpose in the direction of the fissure, 
and cementing the edges thus softened by the addition of 
melted bronze. This is, I suspect, a process never adopted in 
our bell founderies. 
Of the value of his further directions for casting, &c. I am not 
competent to judge ; they appear tolerably full. At p. 109, he 
mentions, that in the manufactory of bronze, lead was occasion- 
ally substituted m part for tin, as being cheaper. C. del Far le 
Palle di Ferro. He states that cannon balls of cast-iron were 
first used in Italy, by Charles, King of France, in his attack on 
Naples, A. D. 1495. He mentions that some added antimony,’ 
others copper, and others arsenic, with the intent of rendering 
the metal more fusible, but objects that itis rendered at the same 
time more brittle. C. di Formare Rilievi. He appears to have: 
been acquainted with all the modes of casting and modelling 
now in use. He much praises the ingenuity of a Siennese: 
