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converges into a small space, producing there a very in-tense heat. This application of a lamp is common amongsundry artists, for melting or softening glass or metallinebodies in any particular part, without affecting the restof the mass; as in soldering metals, making balls forthermometers, &c. It is likewise very commodious forthe expeditious performance of many kinds of experi-ments, where only a small quantity of matter is to beacted upon by the heat : a little gold or silver, laid ina cavity made in a solid piece of charcoal, and exposedto the concentrated flame, melts almost instantaneously ;and a little lead, placed in a cupel, may thus be quicklyworked off or turned to scoria, so as to discover whetherit contains any considerable proportion of the noblemetals.

A bellows of the above construction is worked withvery little labour. It is made still lighter and more com-modious, by using a stiff rod, for moving the lowerboard, instead of the flexible cord or chain commonlyemployed. By the rod, its motion is made to followthat of the hand : whereas, with the cord or chain, itcannot sink fast enough without a considerable additionalweight, and, in raising it again, the hand has thisweight to overcome at the fame time with the weighton the upper board by which the air is forced out.

The trouble of using bellows has by some been pro-posed to be dispensed with, by substituting the æolipile.This instrument is a strong copper vessel, with a neckturned to one side, and terminating in a very smallaperture. The vessel being about half silled with water,and set on some burning charcoal, in any convenientlittle furnace, such as one of our pots, with its neck di-rected to, and placed at a small distance from, the fireto be excited; as soon as the water begins to boil, an

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