

SPICES AND CONDIMENTS. 169 



and (c) by determining the amount neutralized by the distillate from a weighed quan- 

 tity of pure ammonium chloride boiled with an excess of sodium hydrate. 



(2) Standard ammonia whose strength, relative to the acid, has been accurately 

 determined. 



(3) U C. P." sulphuric acid, Sp. Gr. 1.83, free from nitrates and also from ammo- 

 nium sulphate, which is sometimes added in the process of manufacture to destroy 

 oxides of nitrogen. 



(4) Mercuric ox'de, HgO, prepared in the wet way. That prepared from mercury 

 nitrate cannot safely be used. 



(5) Potassium permanganate tolerably finely pulverized. 



(6) Granulated zinc. 



(7) A solution of 40 grams of commercial potassium sulphide in one liter of water- 



(8) A saturated solution of sodium hydrate free from nitrates, which are sometimes 

 added in the process of manufacture to destroy organic matter and improve the color 

 of the product. 



(9) Solution of cochineal prepared according to Fresenius's Quantitative Analysis, 

 second American edition, page 679. 



(10) Burettes should be calibrated in all cases by the user. 



(11) Digestion flasks of hard, moderately thick, well-annealed glass. These flasks 

 are about 9 inches long, with a round, pear-shaped bottom, having a maximum di- 

 ameter of 2 inches, and tapering out gradually in a long neck, which is three-fourth- 

 of an inch in diameter at the narrowest part, and flared a little at the edge. The 

 total capacity is 225 to 250 cubic centimeters. 



(12) Distillation flasks of ordinary shape, 550 cubic centimeters' capacity, and fitted 

 with a rubber stopper and a bulb tube above to prevent the possibility of sodium 

 hydrate being carried over mechanically during distillation. This is adjusted to the 

 tube of the condenser by a rubber tube. 



(13) A condenser. Several forms have been described, no one of which is equally 

 convenient for all laboratories. The essential thing is that the tube which carries 

 the steam to be condensed shall be of block tin. All kinds of glass are decomposed by 

 steam and ammonia vapor, and will give up alkali enough to impair accuracy. (See 

 Kreussler and Henzold, Ber. Berichte, XVII, 34.) The condenser in use in the labora- 

 tory of the Conn. Exp. Station, devised by Professor Johnson, consists of a copper tank 

 supported by a wooden frame, so that its bottom is 11 inches above the work-bench 

 on which it stands. This tank is 16 inches high, 32 inches long, and 3 inches wide from 

 front to back, widening above to 6 inches. It is provided with a water-supply tube 

 which goes to the bottom and a larger overflow pipe above. The block- tin condensing 

 tubes, whose external diameter is f of an inch, 7 in number, enter the tank through 

 holes in the front side of it near the top, above the level of the overflow, and pass 

 down perpendicularly through the tank and out through rubber stoppers tightly fitted 

 into holes in the bottom. They project about \\ inches below the bottom of the tank, 

 and are connected by short rubber tubes with glass bulb tubes of the usual shape, 

 which dip into glass precipitating beakers. These beakers are 6 inches high, 3 

 inches in diameter below, somewhat narrower above, and of about 500 cubic centi- 

 meters capacity. The titration can be made directly in them. The seven distillation 

 flasks are supported on a sheet-iron shelf attached to the wooden frame that supports 

 the tank in front of the latter. Where each flask is to stand a circular hole is cut, 

 with three projecting lips, which support the wire gauze under the flask, and three 

 other lips which hold the flask in place and prevent its moving laterally out of place 

 while distillation is going on. Below this sheet-iron shelf is a metal tube carrying 

 seven Bunsen burners, each with a stop-cock like those of a gas combustion furnace. 

 These burners are of larger diameter at the top, which prevents smoking when cov- 

 ered with fine gauze to prevent the flame from striking back. 



(14) The stand for holding the digestion flasks consists of a pan of sheet-iron 29 

 inches long by 8 inches wide, on the front of which is fastened a shelf of sheet-iron 



