FURNITURE. 479 



on wheels coated with finely powdered emery ; and then properly 

 set or mounted. 



Lamps, are often made of brass or bronze; as the astral lamps; 

 which are covered with a spreading glass shade, and have the oil 

 contained in a hollow ring, with tubes leading to the cylinder and 

 wick, so that there is no large reservoir to obstruct the light on the 

 table. They are usually rfrgand lamps, having cylindrical wicks, 

 witli a supply of air rising through the centre : and the draught is 

 farther promoted by a glass chimney around the flame. The brass, 

 or bronze, is cast, in parts which may be soldered together ; and the 

 gilding may be performed by coating the polished metal with an 

 amalgam of gold, which is then heated to drive off the mercury. 

 Gilding on wood, as for the frames of mirrors, is performed by 

 applying gold leaf to a smooth surface covered with whiting, and 

 size, or glue ; and afterwards burnishing it, with smooth iron or 

 steel. Gold and silver plate, as spoons," cups, and the like, are 

 chiefly made by hammering; as also the minor articles of jewelry, 

 of which we have no farther room to speak. 



3. Of Horology, and musical instruments, our notice must be 

 very brief. The motion of clocks, is produced by means of weights; 

 and that of watches and chronometers, by means of the main spring; 

 the pendulum in the former, and the hair spring in the latter, serving 

 merely to regulate and retard the motion, by distributing it through a 

 longer time. In common clocks, the pendulum, in connection with 

 the scapement, acts upon the scape wheel, which rotates once in a 

 minute ; and, by means of wheels and pinions, this wheel governs 

 the motion of the hands. In ivatches, the hair spring acts on the 

 balance wheel, which performs the same office as the scapement in 

 clocks. In the remaining parts of the machinery, clocks and watches 

 are very much alike ; except in regard to the striking part of clocks, 

 a description of which would transcend our present limits. Chrono- 

 meters, differ from watches, chiefly in being larger, with contrivances 

 for keeping time more accurately. 



Musical instruments, are usually classed as either stringed, or 

 wind instruments ; and the latter are blown either by the mouth, or 

 by machinery. The violin, or fiddle ; the viol, or tenor ; the vio- 

 loncello, or bass ; and the violono, or double bass, are all played 

 with a bow ; and are made of thin plates of wood, moulded by pres- 

 sure. Similar to these, are the lute, and guitar, which are played 

 with the fingers. The lyre, and harp, are also played with the 

 fingers ; but the lyre has a body, and the harp only a frame ; with 

 strings of animal membrane. The piano, has wires for strings ; 

 with keys, acting on levers, and so arranged that the fingers striking 

 the keys, cause the wires to be struck and sounded. Of mouth and 

 fingered instruments, the flute, clarionet, and bassoon, are made of 

 wood, turned in a lathe ; but the trumpet, bugle, and horn, are made 

 of brass or silver. The organ, the grandest of musical instruments, 

 is an assemblage of pipes, opened or closed by the action of the 

 keys, and receiving air from the wind chest, so as to sound when 

 opened. Pulsatile instruments, are formed like the drum, and tarn- 



