Report and Papers on Public Health Volume . 4
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1883 edition. Excerpt: ...flat. Flat-bottomed dishes have a great advantage over the hemispherical in rapid evaporation. A flat circular piece of platinum, about 7 ctm. in diameter, is very convenient for covering the small dishes when they are used to ignite substances that are liable to decrepitate. When all crackling has ceased they are removed, ignited, and the ash brushed into the dish. Porcelain crucibles, a dozen each of Nos. 0 and 1, will be found useful. Porcelain crucibles must be used in the ignition of all substances containing easily reducible metals such as plumbic sulphate and argentic chloride. Porcelain dishes, two or three nests of half a dozen each, the largest holding a half-litre. The four-inch size is very convenient for general use, and it is best to have at least half a dozen of these. Beakers.--The wide form with lips known as Griffin's are the most convenient. Half a dozen nests are not too many. Watch-Glasses.--A dozen three-inch with edges ground to fit. These are very convenient for holding substances in which we wish to determine the moisture. For this purpose two of them are used: they may be held together while the substance is being weighed, either by a rubber band, or best by a spring clip. The spring clip is easily made by taking a brass wire of about 2 mm. in diameter and 20 ctm. in length, bending a ring on each end of this of about 2 ctm. in diameter then bending the wire in the middle so that the rings will come opposite to each other. The wire should be what is known as spring brass. A dozen four-inch watch-glasses. These are very convenient for covering beakers and other dishes while boiling, to prevent loss. Gas-Lamps.--A blast lamp and bellows for intense heat. The Buffalo (N.Y.) Dental Manufacturing Company make the most...
- 189 x 246 x 3mm | 132g
- 13 Sep 2013
- United States
- black & white illustrations