672

Preparations of Ether.

part III.

tralization by the test of litmus: about a drachm of salt isgenerally sufficient for this purpose ; and in a short time thenitrous ether will rise to the surface, and is to be separated bymeans of a funnel.

" If the ether is required to be very pure, distil it againfrom a water-bath, at a temperature of 140°, to one half. Itsspecific gravity is to that of distilled water, as 900 to 1000."

The action of nitric acid on alcohol is so violent, thatthe formation of ether which it affords, has always been re-garded as a process of great difficulty, to obviate which manyingenious plans have been suggested. The operation whichhas been just described is admirably adapted for procuring itwith facility and safety. It was contrived by Woulfe, and wasfound by Pelletier to succeed better than any other. The sul-phuric acid and the spirit must be mixed with the same degreeof caution as is necessary in preparing sulphuric ether ; andthe receiver must be larger, and kept perfectly cool, witlithe apparatus, described in the formula;, attached to it, whichshould be kept cool by a mixture of snow or ice and muriateof lime.

In the above process, the nitrate of potasli is first decom-posed, and nitric acid formed, which acts upon the alcohoias it evolves. The theory of this action is very obscure: butfrom a number of well contrived experiments Thenard was ledto draw the following conclusions. Both the acid and the al-cohol are decomposed; the oxygen of the former combineswith a large proportion of the hydrogen, and a small quantityof the carbon of the alcohol, and thence result, " 1st, Muchwater and nitrous oxide, and small quantities of carbonic acid,nitrous acid, and nitric oxide. 2dly, The separation of a smallquantity of nitrogen, and the formation of much nitric etherby the combination in large quantity of the two elements ofthe nitric acid, with the alcohol from which the large propor-tion of hydrogen and small proportion of carbon have beenabstracted. 3dly, The formation of acetic acid, and of a mar-ter disposed to pass to the state of charcoal, by the combina-tion, in certain proportions, of the hydrogen and carbon of thealcohol with the oxygen of the nitric acid." 1

Qualities. — Nitrous, or rather nitric ether has a strongethereal odour, but is less fragrant than sulphuric ether. Itstaste is strong and peculiar; and its colour slightly yellow,probably arising from the presence of a small portion of nitricoxide. When highly rectified, its specific gravity is 0'866 *:it is more volatile than sulphuric ether, boiling at a tempera-

' Murray's Chemistry, 2d ed. iv. 447-

* Duncan, New Edinburgh Dispensatory, &th ed, 567.