[7] See post, p 33.
[8] "Geographical Survey of Canada."
[9] Ante, p. 27.
USES TO WHICH ASBESTOS IS APPLIED.
In regard to the many varied uses to which this mineral is now put, foremost must be placed the numerous valuable articles manufactured for engineering purposes.
Were I to attempt to enumerate the various kinds of packing, mostly in the shape of millboard, in use for all kinds of engines, for steam joints, cylinder and steam chest covers, pipe flanges, &c., this part of my little book would have the appearance of a manufacturer's catalogue.
The rapidly increasing favour with which high pressure steam is now regarded by engineers, recently necessitated the introduction of a packing capable of resisting the higher temperatures and pressures; as a consequence manufacturers of asbestos goods had to devise improved methods of manufacture in order to meet the new condition of things, and this they succeeded in doing in a way to give universal satisfaction.
For washers asbestos has many advantages over rubber; its weight is less, they can be frequently used, and half the thickness of rubber is mostly sufficient.
The fibre, Sir Frederick Abel says, is as effectual for closing the breeches of big guns so as to prevent the passage of gas, as for ensuring safety, in the same way, for miners' lamps. In these last, it had for a long time been found very difficult to get a good joint between the metallic and the glass parts of the safety lamp, and a great many different materials were tried for filling these joints in such a way that air should not be able to pass through. In many cases, the air was contaminated with a certain amount of gaseous material which would be likely to render the whole explosive, and if this got through the joint between the glass and the metal, there would be very serious risk of explosion. After a great number of substances had been tried and found unsatisfactory, some hundreds of experiments were made by Sir Frederick Abel and Sir Warington Smyth, with asbestos washers, which, in the end, were found to maintain their condition most admirably.