Scientific Intelligence — Chemistry and the Arts. 201 



of magnesium, and to add sea-salt in excess — such Is the process to be 

 carried on." M. Balard adds, that the sulphate of soda thus obtained is 

 hydrated, but pure ; it does not contain sulphate of magnesia, and is free 

 from the excess of acid and the proportion of iron which are frequently 

 found in the sulphate of soda of commerce {L'Institut, No. 563.) 



33. Liquefaction of Nitrous Oxide. — Paris Academy of Sciences, Nov. 

 18. 1844. — A communication was read from M. Natterer jun., of Vienna. 

 When, several years ago, M. Thilorier succeeded in liquefying and soli- 

 difying carbonic acid gas by means of a pressure estimated at 70 at- 

 mospheres, it was generally inferred that there was no gas of any kind, 

 which, by means of intense cold and powerful compression, might not be 

 brought to a liquid state. M. Natterer now informs the Academy, that he 

 had succeeded in liquefying a gas well known to chemists, and, indeed, to 

 the public generally, from its exhilarating properties, which have given 

 to it the name of laughing-gas. He has done this by compressing it 

 with a small iron pump, in a piece of wrought iron, at a pressure of 50 

 atmospheres. The liquid thus obtained was very sweet and fluid, and 

 occupied about the jJoth part of the volume of the gas which furnished 

 it; and he was able to keep it in the liquid state several hours ex- 

 posed to the external air. If the skin was touched with this liquid it 

 caused intense pain, as from a burn. M. Natterer obtained about half 

 a pint of the liquid, and was therefore able, with such a quantity, to 

 make several experiments. — [Athenceum, No. 892, p. 1099.) 



34. Professor Faraday on the Liquefaction and Solidification of 

 Bodies generally existing as Gases. — Royal Society, London, Jan- 

 uary 16. 1845— The method employed by the author for examin- 

 ing the capability of gases to as.sume the liquid or solid form, con- 

 sisted in combining the condensing powers of mechanical compression 

 with that of very considerable depressions of temperature. The 

 first object was obtained by the successive action of two air-pumps : 

 the first having a piston of one inch in diameter, by which the gas 

 to be condensed was forced into the cylinder of the second pump, the 

 diameter of whose piston was only half an inch. The tubes into 

 which the air, thus further condensed, was made to pass, were of 

 green bottle glass, from one-sixth to one-quarter of an inch in ex- 

 ternal diameter, and had a curvature at one portion of their length 

 adapted to immersion in a cooling mixture. They were provided 

 with suitable .stop^cocks, screws, connecting pieces, and terminal 

 caps, all very carefully made, and rendered sufficiently air-tiwht to 

 retain their gaseous contents under the circumstances of the experi- 

 ments, and when they were sustaining a pressure of fifty atmo- 

 spheres, as ascertained by mercurial gauges connected with the appa- 

 ratu.s. Cold was applied to the curved portions of the tube, by 

 their immersion in a bath of Thiloi'icr's mixture of solid carbonic 

 acid and ether. The degree of cold thus produced, when the mix- 



