Home › Miscellaneous Receipts › Phial Barometer

Phial Barometer

Take a com- varnish blackened in a flame so as to see mon phial and cut off the rim and part of the plainly the figures afterward drawn on it. Be neck with a file. This may also be effected careful, when doing this, to make a clear drawby means of a piece of cord passed round it, ing or writing in which the shell is exposed and moved rapidly to and fro, in a sawing at the bottom of every line, as any remaining direction; the one end being held in the left varnish would protect those parts, and the hand and the other fastened to any convenient writing would not be brought out. object, while the righthand holds and movesthe acid, either strong acetic, diluted nitric, or phial; when heated, dip it suddenly into cold muriatic, is then applied, and when its action water, and the part will crack off. (See Nos. is sufficient it is washed off with water, the 2368, &c.) Then nearly fill the phial with varnish is rubbed off with turpentine or alcoclean water, place your finger on the mouth, hol, when the drawing or lettering will apand invert it; withdraw your finger, and sus-pear, and look as if cut in with an engraver's pend it in this position with a a piece of wire or tool. The design may also be drawn with twine. In dry weather the under surface of varnish on the shell by means of a fine brush, the water will be level with the neck of the then the acid will dissolve the surface around bottle, or even concave; in damp weather, on the lines drawn, and the writing will appear the contrary, a drop will appear at the mouth in relief, the letters being elevated in place of and continue until it falls, and is then followed being sunk in as by the former process. The by another in the same way. latter is the more common way in which these