714 CAPSTAN 



ito probable usefulness as a new article of commerce, but also from two very extraor- 

 dinary characteristics which it is found to possess, viz., that, in a liquid state, it has 

 less specific gravity than any other liquid then known to the chemists, being consider- 

 ably lighter than sulphuric ether, and, in a state of vapour, is heavier than the most 

 ponderous of the gases. 



This material (when mixed with alcohol) is a solvent of all the resins, and 

 particularly of copal, which it dissolves without artificial heat, at the ordinary tem- 

 perature of the atmosphere ; a property possessed by no other solvent known ; and 

 hence it is peculiarly useful for making varnishes in general. It also mixes readily 

 with oils, and will be found to be a valuable and cheap menstruum for liquefying oil- 

 paints ; and without in the slightest degree affecting the most delicate colours, will, 

 from its ready evaporation, cause the paint to dry almost instantly. 



Cocoa-nut oil, at the common temperature of the atmosphere, always assumes a con- 

 crete form ; but a portion of this caoutchoucine mixed with it will cause the oil to 

 become fluid, and to retain sufficient fluidity to burn in a common lamp with extraor- 

 dinary brilliancy. 



Caoutchoucine is extremely volatile; and yet its vapour is so exceedingly heavy, 

 that it may bo poured, without the liquor, from one vessel into another, like water. 

 One of the real practical objections to caoutchoucine seemed to be its easy decom- 

 position. Messrs. Enderby and Barnard found that, if exposed to air, and especially 

 if a small quantity of water was present, that it was speedily decomposed, changing 

 colour to deep brown or black. Specimens, however, remain perfectly clear and 

 without change, in bottles, after twenty years. 



After caoutchouc has been subjected to destructive distillation, and the caoutchoucine 

 or volatile oil of caoutchouc has distilled off, there remains in the retort a residual mass 

 which, when dissolved in oil, forms a varnish impervious to moisture, and consequently 

 much used by shipwrights. 



CAPERS. The Capparis spinosa, the flower-buds of which constitute the capers 

 of the shops. Their quality depends exclusively upon the age at which they are 

 gathered, the smallest and youngest being the most delicate and the dearest ; and the 

 largest, the coarsest and cheapest. The buds are plucked before they open, and 

 thrown into strong vinegar, slightly salted, where they are pickled. The crop of each 

 day is added to the same vinegar tub, so that in the course of the six months during 

 which the caper-shrub flowers, the vessel gets filled, and is sold to persons who sort 

 the capers by means of copper sieves. This metal is attacked by the acid, wherefrom 

 the fruit acquires a green colour, much admired by ignorant connoisseurs. About 

 G0,000lbs. a year are consumed in this country. 



The capsules of the caper spurge, Euphorbia Lathyris, are sometimes pickled as a 

 substitute for capers ; but although the acid destroys some of the acrid properties, the 

 free use of them is dangerous. Pereira. 



The unripe fruit of the garden Nasturtium (Tropaotum majus) is also pickled as a 

 substitute for capers. 



CAPXXiXiAIRE. Originally a kind of syrup, extracted from maiden-hair. The 

 term is now applied to a finely clarified simple syrup, which is made usually with 

 orange-flower water. 



CAPNO1V1ORE. A substance discovered by Eeichenbach in wood-tar. 



CAPRYLAirciUE. C 18 H 19 N (C 8 H 19 W). A volatile base obtained by Squire, 

 and also by Cahours, by acting on ammonia with iodide of capryle. It is homologous 

 with methylamine, &c. C. G. W. 



CAPSICUM. The dried ripe fruit of Capsicum fastigiatum, imported from 

 Zanzibar, known in commerce as Guinea Pepper and Pod Peyper. See PEPPER. 



CAPSTAN 1 . (Cabestan, Fr. ; Spille, Ger.) A machine whereon the cable is 

 wound successively in weighing the anchor of a vessel. It is a species of wheel and 

 axle ; the axle being vertical, and pierced with holes near its top for the insertion of 

 the ends of horizontal levers, called handspikes, which represent the wheel. These 

 are turned by the force of men moving in a circle. The power applied to the lever is 

 to the resistance to be overcome (the weight of the anchor, for example), when the 

 forces are in equilibria, as the radius of the cylinder round which the cable is coiled is 

 to the circumference described by the power. It is manifest that the radius of the 

 axle must be augmented in this computation by half the diameter of the cable, which 

 is supposed to lie always one coil thick upon it. The force of a man thus applied, 

 has been commonly estimated as equal to the traction of 27 pounds hanging over a 

 pulley. Friction being so variable a quantity in capstans, -renders the exact calcula- 

 tion of its mechanical effect somewhat uncertain. A stout man, stationed near the 

 bottom of the axle, holds fast the loose part of the cable, which has already made two 

 or three turns ; and, being aided by its friction upon the wood, he both prevents it 

 from slipping backwards, and uncoils each turn as it is progressively made. 



