Su ON JEWS’ TIN. 
The powder was then digested with Aqua Regia, when the 
solution so obtained yielded .5 gr. of peroxide of iron, .21 of tin, 
and .2 silica. 
What remained after this treatment was dark brown, very 
heavy, and much like ordinary “black tin” of good quality, in 
appearance ; when dried it weighed 43.2 grains. 
This was reduced in a crucible by Cyanide of Potassium, and 
yielded 34.12 grains of Metallic Tinto 43.5 gr. of Sn O,. 
The quantities thus obtained were calculated to per-centages 
with the following result :— 
Moisture evolved’ at 120°C 2. nee 6.25 
Mie Gallic WE tae ccc widetae los aase teon nea Renee 43 
@hioriderot linea tacseceen cee ese eee 1.66 
Peroxidevot Wine. socesae Sse ceeaeecmsen en ae 90.62 
Reroxideror Lronurcnace eee eee 1.04 
STILT: Peete tae meaner iy arent am REN SRO a a 4] 
100.41 
The crust therefore appears to be composed chiefly of peroxide 
of tin, somewhat resembling that native variety of Cassiterite 
called “ Wood-tin,” but neither so hard nor so heavy. It has 
no doubt been formed by the slow oxidation of the outer surface 
of the block of Metallic tin. The slowness of the change is, 
perhaps, indicated by the dense condition of the incrustation.* 
Dec. 27, 1871. 
* On a similar sample of the same specimen, Mr. James Napier, F.C.S., 
remarks (20th December, 1871) :— 
“The incrustation which invests the mass of Jew’s-house tin from Tre- 
methack-moor is a pure peroxide of tin with a mere trace of iron;—in short— 
the metal has been reconverted into tin-stone. This is of exceeding interest, 
as it shows how pure the metal must have been. All analyses of ancient 
bronze, however, show that the earliest are of the best quality.” 
