Crape. 



Place 



QCkVl. 

 Kg 6. 



r$7. 



Plate 



ccxvh. 



rigs. 1,2. 



m 



318 CRAN E. 



wards the post to leave space for the barrel, and are Ditto wheel h, hi which the pinion $t. (ii» Crane 



brought so nearly together at the extremity to admit g works 4 0|.—1@0 teeth _ \L „ V 



only the pulley between them. Chains are generally Ditto chain barrel i 14 ■_- -nJ 



used to cranes exposed to the weather ; and it is a con- Ditto friction rollers for chain ... 9 



siderable improvement to the barrels on which they The diameters of the wheels and pinions are taken 



wind, to have a spiral groove or hollow to receive them, at the pitch line. 



as it prevents snapping and jerks from the climbing This crane was made by Messrs Lloyd and Ostell, 



of the chain. This crane, with the frames 1^ inch thick, London, and is warranted by them to carry eight tons # 



will lift five tons with safety. with safety. It has occasionally been loaded with 



Fig. 6. is a crane suitable for an iron foundry, the top ten tons without appearing in the least strained. It 



pivot being supported by the roof: it is here introduced cost, (1813,) including brickwork, timber, and fixing, 



to show one of the methods of moving the pulley block, L. 350. 



so useful in many cases. The gib is formed by two iron The remaining Figures of Plate CCXVH. represent Plate 



plates, between which the pulley block slides, being sup- the double crane now in use (1S13) for constructing p CXV ^L' 



ported by the top edges of the gibs ; to the pulley block the breakwater for protecting the entrance to Aberdeen '%• 



is attached a moveable rack into which a pinion works ; harbour. 



on the same axis with the pinion is fixed a larger wheel, Fig. 4. represents a transverse view of the crane, 



into which another pinion works to give power to working gear, and rollers for moving the crane for- 



slide the block when a considerable weight is appended. wards. 



These are turned by pulling a chain which works into Fig. 5. is a longitudinal view of the crane and part 



aji angular groove of a wheel placed on the same axis of the breakwater, with one gib laying a stone on the 



with the latter pinion. The plan will show the other building, and another lifting a stone from the waggon, 



parts of the crane, which will raise a weight often tons which, with the railway, comes under the crane, 

 with safety; the plates of the gibs being two inches thick. Fig. 6. exhibits apian of the crane, with waggons 



Fig. 7. is a barrel fixed between two iron frames, and railways, as they are laid on when the work ad- 



and a wheel and pinion to increase the power of a man vances. 



at the winch : this is called a crab, and is most useful Fig. 7. shews an enlarged side view of the sliding 



as a portable machine where mechanical power is re- carriage at m and n, Fig. 5, for laying the stones either 



quired. close to the shaft, or as far out as the gib will reach. 



For the drawings and descriptions of these cast iron It is worked by a sheave and rope passing over the 



cranes, the Editor has been indebted to Mr Jessop, point of the gib, and down by the side of the spindle, 

 junior. Fig. 8. is a plan of the sliding carriage and the 



Figs. 1. and 2. are a side and back view of a pit crane sheave, over which the principal working chain or 



erected in Messrs Sargent and Rutty's wharf, on the rope passes, and is attached to the working gear, which 



Grand Junction Canal at Paddington. It is composed is placed in the middle to save room, 

 of a cast iron frame shaft, with an oak gib and brace. For the drawings and description of this crane, the 



It has tln-ee different powers, and each power is a dou- Editor is indebted to Mr Gibbs, who superintends the 



ble purchase. The height of the shaft is 20 feet, of improvements of the harbour at Aberdeen, 

 which 11 feet is below the surface of the ground; it 



rests on a gudgeon about 6 inches diameter, and turns The cranes used for building the locks, &c. on the 

 in a brass pot. At the surface of the ground two plates Caledonian canal, have a shaft about 40 feet high and 

 are fixed to the shaft about 4^ inches asunder, between one foot square ; they turn upon a gudgeon at the bot- 

 which are five rollers ; when the crane is turned, these torn. At the top is a similar gudgeon, and a plate with 

 i-ollers move round the inside of a cast iron ring, which four arms, and a hole in the centre is dropped upon it; 

 is fixed to timbers secured on the top of the wall of the to each of these arms is fixed a guy rope, which is car- 

 pit ; the disposition of these rollers will be seen in Fig. ried to such a distance from the shaft, that when the 

 3. The ends of the gib and brace are received into crane turns round, the gib may keep clear of it. The 

 sockets cast in the shaft, and secured there by wrought lower end is thus connected with _ a pair of pulley 

 iron straps. The gib is about 21 feet long, 12 inches blocks previously fastened to a pile driven in the ground 

 bv 10^ at the shaft, and 16 inches by 12 at the outer for that purpose, and then drawn tight and secured, 

 end; the brace 10 inches square, the frame which The gib is 26 feet long and 10 inches square, fixed a 

 composes the shaft is three inches in thickness ; 1 foot little higher than the middle of the shaft, supported 

 4 inches in breadth at the surface of the ground, and from below by a brace, and suspended from above by 

 •diminishes to 6 inches in breadth at the top, and to a wrought iron bolt one inch square. It is worked by 

 about seven niches at the bottom. a common wheel and pinion. 



Fti In , It is advisable that the axis of the winch should be 



Diameter of the winch is 3 0. three feet from the surface of the ground, this being 



Ditto pinion a 5\. — 10 leaves. the height at which a man can most conveniently work 



Ditto wheel b, in which the pinion it ; its radius should be 1 foot 6 inches, which is as 



a works 3 4i. — 84 teetli. large as an ordinary man can conveniently turn, and by 



Ditto pinion c 7|.— 15 leaves, making it less, power is lost. 



Ditto wheel d, in which the pinion CRANICHIS, a genus of plants of the class Gynan- 



c works 3 If. 80 teeth, dria, and order Monandria. See Botany, p. 314. 



Ditto pinion c 1 3f .— 32 leaves. CRANIOGNOMY. See the following articles. 



Ditto wheel f, in which the pinion CRANIOLOGY, (from H mm, I he skull, and toyts, 



e works 2 5\. 62 teeth. a discourse,) is a science teaching us to investigate the 



•Ditto pinion g (common to all the form, structure, and uses of the skulls in various am- 



iliree powers) 5^.-11 leaves, mals-, by which we learn their specific differences, axaf 



