|
Main
- books.jibble.org
My Books
- IRC Hacks
Misc. Articles
- Meaning of Jibble
- M4 Su Doku
- Computer Scrapbooking
- Setting up Java
- Bootable Java
- Cookies in Java
- Dynamic Graphs
- Social Shakespeare
External Links
- Paul Mutton
- Jibble Photo Gallery
- Jibble Forums
- Google Landmarks
- Jibble Shop
- Free Books
- Intershot Ltd
|
books.jibble.org
Previous Page
| Next Page
Page 36
There are cases when gold is contained in ores in what is known as a
perfectly "free" form--that is, there is an absence of all sulphides,
arsenides, etc.--when it is not practicable to extract it either with
the ordinary forms of quicksilver amalgamation of or any process of
chlorination, without first roasting. This is because the finer gold
is locked up inside fine grains of silica and hydrated oxide of iron.
No ordinary crushing will bring this fine enough, but when roasting is
resorted to by drawing it rapidly through a furnace heated to a cherry
red, these grains are split up so that chlorine gas is enabled to
penetrate to the gold.
It may be said that an equally clever chemist will be required to work
this improved process as compared with those that have, one by one,
fallen into disuse, mainly from want of knowledge among the operators.
To a certain extent this is so. The natural chemical actions are not
so delicate, but an ignorant operator would spoil this process, as he
does nearly every other. When a reef is discovered, practice shows
that its strongest characteristics are consistently carried throughout
it wherever it bears gold. Before Messrs. Newbery and Vautin leave a
purchaser to deal himself with their process, they get large samples
of his ore to their works and there experiment continually until a
practically perfect result is obtained; then any one with a moderate
amount of knowledge can work with the formula supplied. It has been
their experience that the ore from any two mines rarely presents the
same characteristics. Experiments are begun by treating very coarse
crushings. These, if not satisfactory, are gradually reduced until the
desired result is obtained.
To treat the whole body of ore from a mine, dry crushing is strongly
recommended. To accomplish this in the most efficient manner, a stone
breaker which will reduce to about � in. cubes is necessary. For
subsequent crushing Kroms rolls have, up to the present time, proved
most satisfactory. They will crush with considerable evenness to a
thirty mesh, which is generally sufficient. The crushings are then
roasted in the ordinary way in a reverberatory furnace and the whole
of the roastings are passed through the machine we have just
described. By this it is claimed that over 90 per cent. of the gold
can be extracted at very much the same cost as the processes now in
general use in gold producing countries, which on the average barely
return 50 per cent. If so, the gentlemen who have brought forward
these improvements deserve all the success their process
promises.--_Engineering._
* * * * *
APPARATUS FOR EXERCISING THE MUSCLES.
The apparatus herewith illustrated consists of a wooden base, which
may be bolted to the floor, and which supports two wooden uprights, to
which is affixed the apparatus designed to exercise the legs. The
apparatus for exercising the arms is mounted upon a second frame that
slides up and down the wooden supports. It is fixed in position at any
height by means of two screws.
[Illustration: APPARATUS FOR EXERCISING THE MUSCLES.]
The apparatus for exercising the legs, as well as the one for the
arms, consists essentially of a fly wheel mounted upon an axle
extending to the second upright and bent into the form of a crank in
the center. The fly wheel is provided with a winch whose arm is
capable of elongation in order to accommodate it to the reach of the
sound limb.
The apparatus for the legs is arranged in a contrary direction, that
is to say, the wheel is on the opposite side of the frame, and upon
the fixed uprights. It is really a velocipede, one of the pedals of
which is movable upon the winch, and is capable of running from the
axle to the extremity, as in the upper apparatus. This pedal has the
form of a shoe, and is provided with two straps to keep the foot in
place and cause it to follow the pedal in its rotary motion. A movable
seat, capable of rising and descending and moving backward and
forward, according to the leg that needs treatment, is fixed back of
the apparatus.
The operation is as follows: Suppose that the atrophied arm is the
left one. The invalid, facing the apparatus, grasps the movable handle
on the crank with his left hand, and revolves the winch with his
right. The left hand being thus carried along, the arm is submitted to
a motion that obliges it to elongate and contract alternately, and the
result is an extension of the muscles which strengthens them.
Previous Page
| Next Page
|
|