C A M 



296 



Camel, 

 Camelina 



PLATE 



CIX. 



I,g 1,2,3 



some mechanical method of carrying the Dutch ves- 

 sels over this obstruction. In 1672, large chests, filled 

 with water, were fastened to the bottom of the ves- 

 sels, and when the water was pumped out of the 

 chests, the ships were buoyed up, and enabled to 

 pass the shallow. This simple and ingenious con- 

 trivance was obviously the origin of the camel, which 

 was invented by Meuves Meindertszoon Bakker, a 

 burgomaster of Amsterdam, in the years 1688 or 

 1690. A similar invention had been made several 

 years before by Cornelius Meyer, a Dutch engineer, 

 who went to Rome to clear the Tyber, and render 

 it navigable ; but it is not so complete a machine as 

 that of Bakker, who is well entitled to be regarded 

 as the original inventor.* 



The camel, which we have represented in Plate 

 CIX. Fig. 1, 2, and 3, consists of two similar hollow 

 vessels, B, C, Fig. 1. constructed in such a manner 

 that they can be applied on each side of the hull of 

 a ship, as is represented in Fig. 3. Each of the 

 hollow vessels B, C, are so formed as to resist the 

 admission of water; and on the deck of each are 

 erected a number of horizontal windlasses, d, d, d, 

 &c. from which ropes def proceed through the 

 tube de, and being carried under the keel of the 

 vessel, pass through similar tubes d' e', from which 

 they are conveyed to the windlasses d'jd', on the 

 deck of the other half of the camel. When this ma- 

 chine is to be employed for the purpose of elevating 

 a ship, the water is permitted to run into each half 

 of the camel, till both the cavities are filled : the 

 rdpe's def, &c. are then cast loose, and the ship is 

 conducted between the two vessels B, C, and large 

 planks are placed horizontally, so as to extend from 

 the portholes of the ship, and rest upon the upper 

 surface of the camel. The ropes def Sic, are then 

 made fast by means of the windlasses d, d' t &c. 

 till the ship is firmly united to the camel. The 

 water is next pumped from the cavites of the 

 camel, by means of the pumps g, g, till die buoyancy 

 of the hollow vessels raises the ship from the sand, 

 and enables it to surmount the obstruction. The 

 length MN of the camel is generally about 127 feet ; 

 the breadth OP, of the one end 22 feet, and the 

 breadth QR, at the other, 13 feet. The hallow part 

 of the vessels B, C, is divided into several compart- 

 ments. An East India ship that draws 15 feet of 

 water, was so much elevated by means of this machine, 

 that it drew only 11, and the largest ships of war in 

 the Dutch service, from 90 to 100 guns, were always 

 enabled to surmount the different sand-banks of the 

 Zuyder Zee. These machines hcfve been likewise 

 used at Venice, and in Russia. For further informa- 

 tion on this subject, see L' Art de batir les vaisseaux, 

 Amsterdam, 1719 ; Leupold's Theatrum Machina- 

 rium, torn. viii. 180, p. 96, tab. 24 ; Wright's 

 Travels; Muschenbroek's Introduct. ad P/iilos. Na- 

 tur. vol. ii. p. 521. The engraving of the camel in 

 Plate CIX., is, we believe, the first that has been 

 given in any English work. (TT) 



CAMELINA, a genus of plants of the class Te- 



C A M 



order Siliculosae. 



See BOTANY, Camellia 



tradynamia, and 

 p. 264-. 



CAMELLIA, a genus of plants of the class s 

 Monadelphia, and order Polyandria. See BOTANY, 

 p. 271. 



CAMELOPARD. See MAMMALIA. 



CAMEO, is the name given to stones of different 

 colours, which contain sculptures in alto or basso 

 relievo. The effect of nature is here combined with 

 art, and the moderns have in vain attempted to imi-. 

 tate these relics of antiquity. 



The onyx is a hard semipellucid stone, formed of 

 several zones or strata of different colours, closely 

 united, and throughout blended together. As the 

 colours are more distinct and opposite, the greater 

 value is put upon the stone. Some species exhibit 

 three colours, and in others only two are seen, of 

 which the upper is of a beautiful white, on a ground 

 of deep gray. 



These two species of stone were selected by the 

 ancients for engravings or sculptures in alto and basso 

 relievo, as the colours would admit, or according to 

 the choice of the artist, and the subjects represented 

 were some of the most noted incidents in antiquity, 

 such as the labours of Hercules, the rape of Proserpine, 

 or the annunciation to Achilles of the death of Pa- 

 troclus. But one chief excellence consists in the 

 ground being absolutely opposite and distinct from 

 the colour of the subject. Thus, a white figure ap- 

 pears in high relief, though the ground be of a deep, 

 shade, or even black ; and the judicious arrangement 

 of the parts, where uniformity of colour is required, 

 most eminently displays the skill of the artist. 



Genuine cameos always bear a high value, propor- 

 tioned to the beauty of the execution and the quality 

 of the stone. They are discovered in various coun- 

 tries, both in the natural state, and preserved from 

 former times. Of late years, some very exquisitely 

 finished have been recovered by Europeans who visit- 

 ed Delhi. 



Though the moderns have been unsuccessful in 

 sculpturing cameos, they have produced beautiful 

 specimens of analogous workmanship in shells. There 

 the interesting events of ancient history are in like 

 manner chosen, and the relief is pure white, while the. 

 ground is blue. This invention is said to be Sicilian 

 origin. 



Another method of imitating the cameos of the 

 ancients has been practised with very great success. 

 Pieces of coloured glass are put into a crucible, 

 alternating with layers of chalk or Spanish white. 

 The crucible is then placed on a fire, the heat of 

 which increases gradually for three hours, till it be- 

 comes very intense. The pieces of glass then turn 

 opaque without losing the original colour, and those 

 pieces which have no colour at all will become milk 

 white like porcelain. If the heat has been well re- 

 gulated, and not raised too high, these opaque pieces 

 of coloured glass may be soldered to one another, so as, 

 to imitate the differently coloured layers of the onyx. 

 The coloured glass which is found in ancient churches, 



Can\co. 



* An account of Meyer's machine will be found in his book, entitled, ISarte di restituire 

 'tJ no Tzvere. Dell' Ingegniero Cornelia Meyer, Olandese. In Roma, J683, fol. 



'l 



Roma, la tralasciata 



