on some ancient metallic Arms and Utensils. 431 
differences of properties most probably depend upon some ex- 
traneous matter ; but in so small a proportion as to have 
hitherto eluded the research of analysis. 
In the case before us, it is probable that a very minute 
proportion of extraneous matter was present in the spear-head 
and sauce-pan, especially as they were made of cast metal ; 
which might be less hard, and less compact in texture, than an 
allay of pure metals containing a smaller proportion of tin to the 
copper, and yet the allay might be less brittle than the cast me- 
tal. This extraneous matter may be oxygen, or sulphur, or 
earth, although in an imperceptible quantity, introduced during 
the fusion. The lituus is harder, and not more brittle than the 
spear-head and sauce-pan ; although it contains less tin. It 
was made'of a plate of metal which had been much hammered, 
and must therefore either originally have been made of purer 
metal than the spear-head and sauce-pan, or have been ren- 
dered purer by hammering. Perhaps metals in general are 
rendered purer, more uniform in texture, and more dense, by 
remelting, than they were immediately after casting from the 
ore; or in the case of steel immediately after cementation ; or 
in the case of allays after the fusion by which the union was 
effected. Accordingly, cast iron is rendered less brittle by re- 
peated fusion ; Mr. Huntsman's cast steel is made by merely 
remelting steel which had been manufactured by cementation ; 
and Mr. Mudge's speculum metal, an allay of copper by tin, 
was not uniform and sufficiently compact till it was remelted. 
The specific gravity of the sauce-pan, and spear-head, was par- 
ticularly increased by fusion, § 3. 2. 3 ; and their texture was 
rendered more uniform and compact, § 2. 
The specific gravities of the ancient metals correspond, as 
mdccxcvi. 3 K 
