380 
On the Copper Works at Singhana. 
[Dec, 
and tin, all of the length of twenty-five feet. These were extended through the leaden 
pipe in a similar manner to that followed with the rods, excepting that they were 
kept stretched by weights, as represented in fig. 3, proportionate to the size of 
the wires. The results, however, were far from satisfactory : in the first two trials 
when weights from 500 to 900 Sa. wt. were used, owing to the want of rollers for 
the weights, I could not be certain that the force of tension was precisely equal at 
both temperatures ; for the stretching of such long wires by the weights neces- 
sary to keep them even, was nearly as much as their expansion : when rollers were 
applied and the weights diminished to 300 and 200 Sa. wt. the discrepancies were 
even greater, especially with the unannealed wires (bx*ass and iron) which perhaps 
changed their form without elongating in proportion : — the metals rendered 
thoroughly soft by annealing, [gold, silver, copper, and steel,] afforded results 
nearly accordant in every case, although some of them differ a good deal from the 
expressions in Ure's table. The zinc wire became ductile at 212° and stretched 
permanently nearly an inch ; the tin wire also stretched more than five inches at 
the same temperature with a very small weight. Nothing therefore could be ascer- 
tained concerning them. The expansions of the rest for 180 degrees were as fol- 
lows : expressed as before. 
Gold ; pure, annealed wire, 1.00146 
Silver; pure, ditto, 1.00157 
Copper; ditto, Piano wire, 1.00142 
Brass ; thick elastic wire, 1.00159 
Steel ; annealed Piano wire, 1.00122 
Iron ; thick unannealed wire, 1.00108 
It is probable, that all of these expansions are too small, and in different propor- 
tions : and I fear the whole must be pronounced unworthy of confidence, although 
some few agree pretty well with former determinations : when any circumstance 
shall put it in my power to operate upon rods of copper, and of the more precious 
metals, the apparatus employed upon the present occasion can be fitted up for the 
purpose, in a few minutes, and indeed it is the exceeding simplicity of the whole 
operation which forms its principal recommendation’ to those who may be desirous 
of making similar researches. 
II. — On the Copper Works at Singhana near Khetri in the Shekhd- 
ivati Country. 
Lat. 28° 05' N. and Long. 75° 53' E. 
The mines whence the copper ore is extracted are situated one kos south-west 
from Singhana, in the range of rocky hills which run for some distance to 
the southward of that town, and seem to be impregnated with metallic oie 
throughout their whole extent ; mines are also wrought at Khetri and Bubai, 
producing many valuable minerals, such as copper, tamba; blue vitriol or sulphate 
of copper, called by the natives lila tdtia, or Icelo toto; alum, phitkarl, and a 
mineral called sehta, which requires a more particular description. 
This sehta looks like a fine grey sand, having the appearance of iron-fili°£ s 
mixed with minute particles of silex and mica; its value, at the mines, being 
from 40 to 100 rupees per maund. It is only produced at Bubai, and IS 
used as an ingredient in making glass, kanch, or women’s wrist-ornaments, 
churay which seem to be made of a vitrified substance, coloured with lac, fob, an 
other pigments. 
