METALS AND THEIR ORES. 13 
Australia, 925.; the Chaudiére region of Canada 885 to 900; while from 
Nova Scotia the gold is very nearly pure. 
The method of extraction first employed is the ordinary stamp process, 
ten small stamps rather lighter than usual, with copper and blanket 
amalgamation. It is thought by those much experienced in quartz mill- 
ing to have been carried on in a crude manner, yet the amount saved 
has been a fair percentage of the assay yield. There were two of these 
mills, one on each side of the river at Lisbon village. 
With the advent of the Electro-Gold company the Thunder-bolt crusher 
replaced the stamps. The rock was heated, or partially roasted. It was 
then crushed dry, and the powder placed in cylinders with water and 
quicksilver, thirty pounds to a ton of ore. This cylinder revolves four 
hours, and the sands flow into a dolly tub, afterwards passing over blan- 
kets. The sulphurets are caught mostly in the tub, and saved for fur- 
ther treatment. The blankets catch the fine gold, and are changed every 
four hours. This mill could treat five tons of rock in ten hours. It was 
the most successful of the various methods tried in New Hampshire. It 
has since been used more extensively in Virginia. Being of little use for 
the extraction of gold from sulphurets, Dr. Rae has added a desulphuriz- 
ing furnace to his works, enabling him to treat ores otherwise intracta- 
ble. We present herewith the original specifications of the patent de- 
scribing this process. 
123,982. United States Patent Office. Fulio H. Rae, of Syracuse, New 
York. Lmprovement in Voltaic Amalgamators for Gold and Silver. 
Specification forming part of Letters Patent No. 123,932, dated February 20, 1872. 
To all whom it may concern: 
Be it known that I, Julio H. Rae, of the city of Syracuse, in the county of Onon- 
daga and state of New York, have invented a new and useful improvement in voltaic 
amalgamators for ore; and I do hereby declare the following to be a full, clear, and 
exact description thereof, which will enable those skilled in the art to make and use 
the same, reference being had to the accompanying drawing forming part of this 
specification, in which drawing,—. 
Fig. 1 represents a longitudinal vertical section of my invention. Fig. 2 is a plan 
or top view of the same. Fig. 3 is a detached longitudinal central section of the 
voltaic cylinder, which forms one of the principal parts of my amalgamator, in a 
larger scale than the previous figure, the line x x, Fig. 4, indicating the plane of 
