is cooled in pounded ice, and the meniscus adjusted to the mark on a by tilting the tube until the limb b has a horizontal position. To the end of this limb a piece of bibulous paper is applied until the liquid sinks to the desired position in the limb a. The Utube is then brought to a vertical position, loose glass caps placed over the ends of the two limbs, the apparatus carefully dried, allowed to stand and weighed. The operation is then repeated with distilled water. An experiment with ethyl bromide gave The correction for weight in air is so small that it may here be neglected. (Sulphuric Ether. Ethyl Oxide.) LITERATURE.-V. Cordus 1544; Boullay (1813), Journ. Pharm. 1, 97; Williamson (1850) Phil. Mag. (3), 37, 350. 300 grms. conc. sulphuric acid. alcohol go per cent. A mixture of 300 grms. conc. sulphuric acid and 170 grms. alcohol, 90 per cent. are heated to 140° in a round-bottomed flask on wire gauze by means of a Bunsen lamp. The flask is closed with a cork pierced with 3 holes. Through one of these a thermometer is inserted and dips into the liquid; through the second FIG. 23. a tube is fitted which reaches just above the surface of the liquid and is attached at its upper end with a vessel containing alcohol (Fig. 23). A bent tube passing through the third hole connects the flask with a long condenser and receiver, both of which must be kept well cooled during the operation. When the temperature of the mixture reaches 140°, 90 per cent. alcohol is run in from the reservoir of alcohol in proportion to the quantity of liquid which distils. The temperature must be maintained constant at 140-145°, which is easily effected by regulating the supply of alcohol. When about treble the quantity of alcohol contained in the original mixture has been converted into ether the distillation is stopped. The liquid in the receiver consists of two layers, and contains in addition to ether, alcohol, water and sulphurous acid. The ethereal layer is drawn off, washed with dilute soda solution, then repeatedly with water, and is dehydrated over pieces of fused calcium chloride. It is rectified on the water-bath. The ether thus purified still contains traces of alcohol and water, which it obstinately retains, and from which it can only be freed by a further treatment with metallic sodium (see p. 5). The ether may be finally distilled on the water-bath over fresh metallic sodium. The receiver in which the ether collects should be cooled with ice, and a calcium chloride tube attached to it to prevent absorption of moisture during the distillation. C2H5OH + H2SO4 = C2H5. SOH + H2O CH. SOH + C2H5OH = С2H5OC2H5 + H2SO Ether. On heating alcohol and sulphuric acid, ethyl sulphate is first formed with elimination of water. In the second phase of the reaction, which occurs at 140°, a second molecule of alcohol is decomposed with the formation of ether, sulphuric acid being regenerated, and the latter can again convert a fresh quantity of alcohol into ether. Properties.-Colourless, mobile liquid; b. p. 35°; sp. gr. 713 at 20°; burns with a luminous flame. Not miscible with water; 9 parts water dissolve I part ether. PREPARATION XLV. CHLOROFORM, CHCl3 Literature. —Liebig (1831), Pogg. Ann. 23, 444; Soubeiran (1832), Ann. Ch. Phys. (2), 48, 131; Dumas (1834), Ann. Ch. Phys. 56, 115. 200 grms. bleaching powder. Two hundred grms. bleaching powder, 800 grms. water and 33 grms. dilute alcohol are placed in a roundbottomed flask connected with a condenser and well mixed into a paste. The mass is carefully heated over wire gauze, preferably with a rose burner. As soon as the reaction begins, the burner is removed and chloroform and water commence to distil over into the receiver, where the former settles to the bottom as a heavy oil. The chloroform is freed from alcohol by shaking with water and dehydrated over calcium chloride. It is finally rectified on the water-bath. 4Ca(OCI)2 + 2C2H5(OH) Calcium Hypochlorite Alcohol = 2CC1,CHO + CaCl, + Chloral. 3Ca(OH)2 + 2H2O 2CCI,CHO+ Ca(OH)2 = 2CHCl3 + Ca(HCO2)2 Chloral Chloroform Calcium Formate. The formation of chloroform is here due to a secondary reaction. By the action of bleaching powder on alcohol, choral is first formed, which decomposes in presence of the calcium hydrate of the bleaching powder into chloroform and calcium formate. Properties.-Colourless liquid possessing an ethereal odour and sweet taste; b. p. 62°; sp. gr. 1'525 at o°; does not burn. LITERATURE-Williamson, Kay (1854), Proc. Roy. Soc. 7, 135; Basset (1864), Chem. Soc. J. (2) 198; Ladenburg, Wichelhaus (1869), Ann. Ch. Pharm. 152, 164; Deutsch (1879), Ber. 12, 116. 58.5 grms. metallic sodium well pressed between filter paper and cut into thin slices are placed in a |