74 Scientific Intelligence, Sfc, 



an aqueous solution of the oil with the hydrate of copper ; chlorine 

 decomposes the spiroilides, and forms chlorides of spiroile — the latter 

 being the basis of the acid. SpiroiUc acid, when carefully prepared 

 by taking care not to add an excess of nitric acid, forms a crystalline 

 mass; or may be sublimed in close vessels. By exposure to the air 

 it becomes yellow ; dissolves readily in alcohol and ether. It consists 

 of carbon 51*58, hydrogen 3*50, oxygen 44*92. Hydrospiroilic acid 

 consists of carbon 66*92, hydrogen 5*35, oxygen 27*73. The spi- 

 roilide of copper consists of carbon 51*71, hydrogen 3*51, oxygen 

 22*51, copper 22 27. The subject has been largely investigated by 

 Pagenstecher and Lowig. — Journ. de JPharm., April, 1836. 



V. — JV^ew Hydrate of Carbonate of Magnesia. 



Dr. Fritzsche observed a deposition of two different salts, in a 

 large quantity of a concentrated solution of carbonate of magnesia in 

 carbonic acid water, which had remained for a winter in a glass 

 vessel. One of these salts consisted of small needles grouped to- 

 gether, which gave by analysis, Mg 0,00^+3 HO. The other 

 salt consisted of plates, and lost some of its water of crystallization 

 by exposure to the air. Its constituents are magnesia 23*70, car- 

 bonic acid 25*39, water 50*91|; and its formula Mg 0,C02 +5 HO. 

 — Poggendorff Annalen xxxvii., 304. 



VI. — Mode of preparing Azote. 



One of the easiest methods of preparing this gas, is to pass a current 

 of chlorine through liquid ammonia. The ammonia is decomposed 

 and muriatic acid is formed. Mr. Emmet has suggested an equally 

 simple method. He fuses in a retort nitrate of ammonia with some 

 pieces of zinc. The metal decomposes the nitric acid ; azote and 

 ammonia are disengaged, and when received over water the latter is 

 absorbed. Mr. Emmet employs, for this experiment, a small cy- 

 linder of zinc, attached to a wire which passes through the tubulure 

 of the retort. By raising or lowering the latter in the nitrate, the 

 escape of the gas may be regulated. — Silliman's American Journal, 

 Feb., 1835. 



VII. — Ice a Non-conductor of Electricity . 



In the 4th series of his electrical researches. Dr. Faraday states 

 that on investigating his new law of electric conduction, "he was 

 suddenly stopped by finding that ice was a non-conductor of elec- 

 tricity.*' He found that a thickness of i^ths of an inch of ice 

 scarcely allowed the electricity to pass at all. Professor Bache, of 

 Pennsylvania University, in commenting upon this observation, 

 (Journal of the Franklin Institute, March, 1836) states that the 

 non-conducting power of ice was well known to Dr Franklin and 

 his associates. In a series of letters to Collinson of London, written 

 in 1747 and 48, Franklin observes <' a dry cake of ice or an icicle 

 held between two in a circle likewise prevents the shock, which we 

 would not expect, as water conducts it so perfectly well." Watson 



