, 
TRANSACTIONS OF THE SECTIONS, 93 
by a hoop of iron, was so split and shattered on the head that it would require to be re- 
headed to. drive.it any further. The other, although sixty-six feet long, was not even 
supported by an iron hoop, and the head is as smooth as if it were dressed off with a 
snew plane. It was driven with a hammer of 50 cwt., and only three feet fall, making 
seventy-five blows a minute, and was put in its place and finished in 44 minutes. 
/ In, addition to other great advantages of driving by a heavy weight over that of 
driving by a light weight, is the immense saving of labour, or whatever moving power 
is employed. 
Dr. Greene advocates the use of this new powerful agent in the contemplated har- 
bours.of refuge which are to be formed along our coasts, and in the recovery of vast 
tracts of land from the sea. : 
[Since the first communication was received, in consequence of the men becoming 
more familiar with the manner of working the machine, some of the huge piles have 
actually been raised from the raft, put in their places, and driven to the required 
depth in two minutes; the operation seldom occupying more than four minutes. | 
On Railway Gradients. By Wittiam FairBairn. 
The author stated that the object of this communication was simply a notice of ex- 
periments then in progress to determine the power of adhesion of the locomotive en- 
gine in the first instance, and the force of traction necessary to work gradients in the 
second. After a brief statement of the progress made in the development of different 
lines of communication and the improvements effected in the locomotive engine, the 
paper went on to state the facilities with which even steep gradients were now sur- 
mounted by the enlarged powers of the engine, more particularly when compared with 
those in use at the commencement and subsequent extension of railway traffic. 
The author proceeded to examine, — 
_ist. The resistance due to friction on the machinery or working parts of the en- 
ne. 
2nd. The resistance of the engine considered as a carriage. 
5rd. The resistance of the waggons, carriages, &c. composing a train; and, 
Lastly, the resistance of the air. 
In treating of these separate heads, the writer instanced the experiments of the 
Comte de Pambour, Dr. Lardner, and Mr. Woods. According to those authorities, 
the resistances were variously stated; first by Pambour, who makes the friction of 
the waggons and steam-engine, when considered as a carriage, equal to 5-76 Ibs. per 
ton, and for the friction of the working parts of the engine 7 lbs. per ton. On this 
assumption the resistance would be 5-76 + 7 = 12-76, or about 13 lbs. per ton for 
the sum of the friction due to the engine (considered as a carriage) on the one hand, 
and the whole of its constituent parts taken collectively on the other. 
_, As respects the resistance of the air, the author gave results from similar experi- 
ments, and haying assumed a velocity of 33 miles an hour, he found a mean resist- 
ance of 2°92, or nearly 3 Ibs. on every square foot of surface exposed to the action of 
the air. Mr, Woods in some recent experiments makes the resistance on a calm day 
(at the same velocity) 3th of the whole weight, which, compared with others, gives 
a total resistance (including friction) of 25 lbs. per ton. This sum was considered a 
fair ayerage of the experiments; and assuming 25 Ibs. as the maximum resistance to 
every ton of a railway train, the author laid before the Section a table of gradients, of 
‘which the following is an abstract :— 
' Gradients. Resistance in Ibs. per ton. 
in 20 onsebwebsene 137-00 
sorrdiiniad osbt vai lige 81-00 
» 60 sesesecesnce 62°33 
poi BOS I -edhiolsas 53-00 
je BOOsivolwe. lecue, dl 47-40 
Seenscsecses 43°66 
0408s | ih Shaiget 40-71 
3, 160 Sescesesscee 39:00 
” 180 steeneceeees 37°44 
» 200 sadecdaeleces 36°20 
el lll oll ne dt ll 
vy 
. 
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