46 NOTICES OF THE MEETINGS. [March 21, 1851. 
equally applicable to clocks and various machines as a motive 
power. 
2. To the raising of weights (Mr. Hodges’ Patent application). — 
Short lengths of caoutchouc (termed by him Vulcanized power-pur- 
chases) are successively drawn down from or lifted to a fixed bearing, 
and attached to any weight which it is required to raise ; when a suf- 
ficient number of these power-purchases is fixed to the weight, 
their combined elastic force lifts it from the ground. Thus ten 
purchases of the elastic strength each of 5Olbs. raise 500 Ibs. 
Each purchase is six inches long and contains about l1oz. of 
vulcanized caoutchouc. These ten purchases, if stretched to their 
limit of elasticity not of their cohesive strength, will lift 650 lbs. 
This power — the accumulation of elastic force — though it obey the 
common law of mechanical powers, differs enough to be distinguished 
as a new mechanical power. 
The same principle is applicable to relieve boats in tow from the 
strain they are subject to, and to easing the strain on ship’s cables, 
especially where several boats are towing one vessel. 
3. Applied as a projectile force. A number of power-purchases, 
attached to the barrel of a gun constructed to project harpoons, 
will exert a power if suddenly relieved proportioned to their aggre- 
gate forces. 
Similar contrivances have been made for projecting balls 200 
yards or more: a charge of No. 4. shot can be thrown 120 yards. 
On the same principle a bow was contrived in which (reversing the 
usual form) the string alone was elastic; this bow throws a 30-inch 
arrow 170 yards. 
There were also exhibited adaptations of this material, for restrain- 
ing furious horses,— for slinging horses whose limbs have been 
broken,— for enabling bed-ridden persons to assist themse]ves,— 
for strengthening feeble joints, and many other new and valuable 
purposes. W. B. 
In the Library, were exhibited ; — 
An antique Atlas (said to have belonged to Prince Talleyrand) 
drawn on parchment by Nicolas Vallard of Dieppe, in 1547, 
illuminated in the style of the ancient Missals, and illustrated 
with views of the various countries and figures of their inhabi- 
tants and animals, and upon which a Lecture was read before the 
Institute at Paris, in 1807, by M. Barbier duBocage [by Sir Thomas 
Phillipps, Bart. M.R.1.] 
British Minerals [presented by Adam Murray, jun. Esq. M.R.I.] 
Piece of Stucco from the Alhambra, and of Tessellated Pavement 
from Glastonbury, Models of Rudders, a Persian Astrolabe, &c. 
{from the United Service Institution]. 
Fish from the Red Sand-Stone, Fifeshire [J. Tennant, Esq. ] 
Specimens of Gutta Percha Manufacture [Messrs. Thorn & Co.] 
