Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . lamp is lighted by blowing a flame „ up and across the wick. When wellcharred, the wick is carefully trimmedparallel to the brass holder. Fletcher Lamp.—The Fletcher blow-pipe lamp, Fig. 293, gives good satisfac-tion, and a modified form, burning solidfats, tallow or paraffine, is especiallyadapted for field work. Supports of Charcoal, Plaster, Etc. Chaycoal.—Charcoal made from soft woods, such as willow orpine, is used to support the substance and receive any coats orsublimates that may form, and, i
Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . lamp is lighted by blowing a flame „ up and across the wick. When wellcharred, the wick is carefully trimmedparallel to the brass holder. Fletcher Lamp.—The Fletcher blow-pipe lamp, Fig. 293, gives good satisfac-tion, and a modified form, burning solidfats, tallow or paraffine, is especiallyadapted for field work. Supports of Charcoal, Plaster, Etc. Chaycoal.—Charcoal made from soft woods, such as willow orpine, is used to support the substance and receive any coats orsublimates that may form, and, in a measure, is a reducing convenient size is 4 inches long, i inch broad, and ^ inch thick. Plaster.—Plaster tablets are used for the same purpose. Theseare prepared by making a paste of plaster of Paris and water, justthick enough to run, which is spread out upon a sheet of oiledglass and smoothed to a uniform thickness {].i to ){) by anothersmaller sheet of glass, which may be conveniently handled by gum -ming a large cork to one side and using it as a plasterers 86 BLOWPIPE ANALYSIS. While still soft, the paste is cut through with a knife into uniformslabs, 4 by 11^. It is then dried, after which the tablets areeasily detached. Aluminum and Glass.—Ross used supports of aluminum plateand recently Goldschmidt has recommended catching the sub-limates on glass plates upon which they can be microscopicallyexamined or submitted to wet treatment. Miscellaneous Apparatus : Each student should have at his desk, in addition to blowpipe,blowpipe-lamp, charcoal and plaster : Forceps, with platinum tips for fusion tests. The most con-venient form is shown. Fig. 294, the platinum ends projecting atleast three-fourths of an inch. Fig. 294. Fig. 295. Platinum Wire and Holder.—Wire of the thickness of about 24 Am. standard wire gauge. The handle for holding this is sometimes only a short piece of small glass tubing, into the end of which the wire is fused. A hol
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