Mr Dumas, the distinguished chemist, in giving an account to a scientific Society in Paris of the liquefaction and solidification of gases, stated that the specimen of oxygen produced by Mr Pictet of Geneva was the size of a hen’s egg, and resembled snow in the solid form, and water in the liquid form. Theoretically he had concluded that the density of liquid oxygen would be about the same as that of water; and this has been confirmed by experiment. As regards hydrogen, Mr Dumas explained that it was liquefied under a pressure of six hundred and fifty atmospheres with cold minus one hundred and forty degrees; and by evaporating the liquid thus obtained, the solid condition, shewing the colour of blue steel, was arrived at. Many years ago this possibility was foreseen, and the most advanced chemists admitted the existence of a theoretical metal—hydrogenium. ‘This confirmation of the real nature of hydrogen,’ continued Mr Dumas, ‘is not to be regarded merely as a theoretical result useful to pure science; it appears to be of great importance for the future of industry. A certain knowledge of the metallic nature of hydrogen will have a certain influence on metallurgy, of which manufacturing arts will take advantage.’ The phonograph has been exhibited, and made the subject of lectures and experiments in many places, and as we anticipated, has given ample demonstration that the statements put forth concerning it are true. Marvellous as the fact may appear, all the words spoken into the instrument seem to be there stored up ready for repetition whenever excited by the cylinder of tinfoil. They do not come out quite in the same tone as that in which they go in; but they are perfectly distinct, and retain the characteristics of the speaker or singer. At a scientific meeting in London, one of the company sung _God Save the Queen_ into the phonograph. On coming to the highest note, he had to make three attempts before he could reach it; and these failures excited much merriment when the stanza was (only too faithfully) repeated by the instrument. The same air was sung and produced without failures, and a comic ditty was sung and inscribed on the same cylinder: and very curious it was afterwards to hear the stately movement of the national hymn accompanied by the jingling notes of the funny melody. An instrument so ingenious as this ought to be applicable to many useful purposes. Already there are improvements on the original invention, and we shall doubtless hear of others.