p R i: 



i .-, i 



P R E 



the charge and elevation to the distance of the 



,ciin(il ti- Ms-. .lolin Murray, lectu: 

 chemistry, tint :i mu-!.rt and a musket bullet i 



i place Of the mortar and ball ofCap- 

 l.mhy's apparatus. Hi- proposes to affix a line of 

 whip-cord to arrows of ash, hickory, and sometimes 

 iron, loosely filling tin- calibre of the musket, and to fire 

 off these arrows with a charge of gunpowder less than 

 the usual quantity. The arrows are three or four inches 

 than the barrel of the musket, and are shod 

 with iron at the point, having an eye through which 

 the line is thrown. The lower end enters a socket, 

 which must be in complete contact with the wadding 

 of the piece. The average distance to which an arrow 

 and a logline were projected, was about 230 feet, 

 though in one case, an iron rod was carried 333 feet; 

 but in this case the line was favourably placed. Mr. 

 Murray considered that whin-cord was strong enough 

 to carry a log-line, arid a log-line strong enough to 

 carry a rope on board. 



Mr. Murray has proposed the same method for pro- 

 jecting the arrow over lofty buildings on fire, and 

 thus to carry a line attached to a lengthened rope- 

 ladder, which could be drawn over the roof to the 

 other side, and thus instantaneously establish free 

 egress for the unfortunate inmates. The ends of the 

 rope-ladder should be fastened into the pavement by 

 means of iron staples. 



An apparatus for saving lives in cases of shipwreck 

 by Mr. H. Trengrouse, is described in the 38th volume 

 of the Transactions of the Society of Arts, p. 161 165. 

 The projecting force which he used in the apparatus 

 is a rocket ; and it was found that a rocket of 8 oz. 

 with a mackerel line attached to its stick, ranged to the 

 distance of 180 yards, and that a pound rocket, in si- 

 milar circumstances, ranged 212 yards. The rocket is 

 placed in a copper instrument, at the end of a musket, 

 charged with a small quantity of powder, without wad- 

 ding ; for the purpose merely of directing and ignit- 

 ing the rocket. The rocket, when lighted by the 

 powder, burns a few seconds before it acquires suffi- 

 cient momentum to quit its situation ; during which 

 time the combustible would be ejected into the barrel 

 of the gun, if it were not prevented by a loosely sus- 

 pended valve, which opens to permit the passage of 

 the charge, but immediately closes, and prevents the 

 barrel from being choked by the retrograde discharge 

 from the rocket. 



In the year 1822, Captain Dansey of the Royal Ar- 

 tillery communicated to the Society of Arts the de- 

 scription of a kite and apparatus for obtaining a com- 

 munication with vessels stranded on a lee shore, or 

 otherwise, where badness of weather renders the appli- 

 cation of the ordinary means impracticable. A sail of 

 light canvass, or holland, being cut to the size, and 

 adapted for the application of the principles of the 

 flying kite, is launched over the vessel, or other point 

 to windward, of the space over which a communication 

 is required, and as soon as it appears to be a sufficient 

 distance, a simple mechanical apparatus is used to de- 

 stroy Us poise, and cause it to fall immediately, but 

 remaining still attached by the line, and moored by a 

 small anchor with which it is furnished. The results 

 of the experiments made by Captain Dansey with a 

 kite of 60 feet of surface, has been in a strong breeze 

 the extension of a line of sixty pounds weight, 350 

 yards long, and 1 inch in circumference. In an- 

 other experiment, he extended a line of 37 pounds 

 weight, 1 ] 00 yards long, and ths of an inch in cir- 



cumference. In using this apparatus, little more at- 

 tention or skill is said to be necessary than in flying 

 an ordinary kite. 



A minute description of this ingenious apparatus, 

 accompanied with drawings, will be found in the 

 Transactions of the Society of Arts, vol. xli. p. 182. 



Among the inventions for preserving lives at sea, 

 we may enumerate: 



1 . The safety buoy and life-boat of Mr. Boyce, con- Enumen- 

 sisting of hollow canvass cylinders, painted and var- tion of 

 nished, and connected with each other. See Tram- olber h 

 actions i>J' the Society of Art i, vol. xxxii. p. ITT. 1 *' 

 1814. 



2. The contrivance of Mr. G. Bray, was, in 1818, of 

 a boat filled with air-boxes, placed under the seats and 

 along the sides. Id. vol. xxxv. p. 172. 



3. Mr Thomas Cook's life-buoy, for preserving the 

 life of a person who falls overboard in the night. Id. 

 vol. xxxvi. p. 121. 



Among the machines for saving persons in the act -Method of 

 of drowning, we may mention a very ingenious one T 'g per 

 which has been used for some time at Duddingstone * n * that 

 Loch, near Edinburgh, under the sanction of the Skat- 



f~, t . A I I I / ' n '"' ICC 



ing Club. As this loch is much resorted to when fro- O f jaket. 

 zen over, for the purpose of skating, several persons 

 have been drowned from the ice giving way in parti- 

 cular places. In order to give assistance to persons 

 who have sunk in the ice, a rope is placed so as to sur- 

 round the whole lake. This rope is at the command 

 of any spectator, at any part of the circuit of the lake, 

 and when any person needs assistance, another at the 

 margin of the lake has only to take hold of the rope, 

 and drag it towards him. The rope must necessarily 

 pass over the spot where the person in danger has 

 sunk ; so that, by taking hqfd of it he may be dragged 

 on the ice, or be enabled to reascend. 



Under our article FIRE ESCAPES, Vol. IX. p. 352, Fire es- 

 we have given an account of various inventions for capes, 

 this purpose. To the machines there described may 

 be added, Mr. Braby's fire-escape, described in the 

 Transactions of the Society of Arts for 1816, vol. xxxix. 

 p. 227. It consists of a car made to slide on a strip 

 of plank, fixed to a pole, and directed by a rope. 



PRESS, is the name given to a machine for com- 

 pressing any substance or substances, and retaining it 

 under that compression as long as it may be requir- 

 ed. 



Various presses, used for general purposes in the 

 arts, have been described under different articles in this 

 work. 



A Simple Lever Press is represented in BRASIAH'S 

 Hank Note Press, described under that article, Vol. 

 IV. p. 403, and represented in Plate LXXVI. In 

 this press, the force of the hand applied at the extre- 

 mity F, of the lever FD, Fig. J , produces a power at 

 F, where the type on the left hand of E is impressed 

 upon the bank-note above it. 



The Common Lever Press is shown in Fig. 4, Plate 

 LI I. where the two plates CC, BB are pressed toge- 

 ther by means of the screw D and the cast-iron wheel 

 E, to which a lever may also be applied. Another 

 drawing of the same press is shown in the Coining 

 Press, Plate CCI. Fig. 8. 



The Hydrostatic Press of Braraah has been amply 

 described under the articles BANDANA, CRANE, CALEN- 

 DER, and HYDRODYNAMICS. References to other ma- 

 chines described in this work, and acting by compres- 

 sion, will be found under MECHANICS, Vol. XIII. 

 p. 619. 



