TRANSACTIONS OF THE SECTIONS. : 113 
miles per hour, —an unrecorded speed forships of any size, clesehauled, but surprising 
for a vessel of 45 tons, and in a very rough sea. It was, in fact, remarked on board, 
that, as the wind freshened, her pace increased without limit. This agrees with the 
fact stated by Capt. Fishbourne of the Flambeau steamer, on wave lines, that she 
had a speed greatest in the worst weather, as compared with her rival. It is perhaps 
possible to improve sailing vessels greatly, as compared with steamers. When so 
improved, they might be used where sailing vessels nearly compete with steamers at 
present. This may be further helped by the diminution of insurance and of the pre- 
sent unnecessary waste of human life. 
Mr. Bodmer communicated the result of experiments on long and short stroked 
steam-engines. 
Mr. Clarke exhibited the model of a new atmospheric tube, in which the sides 
are elastic enough to close the slit and form a self-acting valve. 
Dr. Bevan exhibited his mode of applying atmospheric air to propulsion. 
Mr. Eyton exhibited the model of a compact form of vertical steam-engine, which 
possessed the advantage of a long connecting-rod. The plan was not quite original, 
but he had applied it with advantage. 
On Vulcanized Caoutchouc. By W. Brocxevon, F.R.S. 
Mr. Brockedon stated that the discovery in this country was due to Mr. Hancock 
of the firm of C. Macintosh and Co., Manchester, and that he made it whilst experi- 
menting to fuse caoutchouc and sulphur together. He found that though the sul- 
phur was at 300°, the rubber, which alone would have melted at about 220° and 
absorbed the sulphur, was thus protected from melting. A chemical union of a cer- 
tain portion of the sulphur with the caoutchouc took place; and it was found that 
this process might be carried far enough to carbonize the caoutchouc to the condition 
of horn, but fever to melt it. Mr. Hancock then united sulphur mechanically with 
rubber ; and also dissolved sulphur in the solvents of caoutchouc; and heating these 
materials so prepared to the necessary degree, found that the change was effected 
called vulcanized. The new properties which rubber thus acquires are most import- 
ant in the hands of mechanical engineers, from the increased and permanent elasticity 
of the vulcanized rubber; it is being brought into extensive application and use for 
railways, lying between the rail or the chair and the sleeper; for the drag and buffer 
springs and side springs of railway carriages, waggons and trucks ; for washers for 
steam, gas, and water-pipes, being permanently elastic at low temperatures as well 
as at very high; even for steam pipes at 50 and 60 lbs. to the inch, they have formed 
a perfect joint. A Nasmyth steam-hammer of 5 tons weight has fallen 18 inches on 
a piece 3 an inch thick and 2 inches square without any injury to the form of the 
rubber. A cannon-ball resting on a piece of vulcanized rubber | inch thick has been 
crushed and broken without leaving, except upon close examination, any trace of its 
effects on the rubber, when a hole like a leech-bite might be found which had closed 
after the blow. The layer of corrugated rubber, which had been placed between the 
rail and the sleeper, after two years’ service on the Great Western Line, betrayed no 
trace of injury or effect of pressure. 
Upon this new material the solvents of common rubber have no longer the action 
of solvents; the rubber slowly absorbs them but is not dissolved by them, and when 
the essential oils are evaporated the vulcanized rubber regains all its strength and 
elasticity. Its elasticity is permanent and invariable ; no cold of our climate has any 
power to harden it, or the heat of any climate to injure it. These are properties which 
cannot fail of bringing it extensively into use in the mechanical arts. 
1846. I 
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