Some important experiments of this nature arc due to Andrews. Having, by mere pressure, partially liquefied carbonic-acid in a glass tube, he raised the temperature gradually, and observed that the demarkation between the liquid and the gas became less and less definite; the capillary curvature of the surface of the liquid also diminishing. At about Fahr., the liquid surface became horizontal, and the liquid disappeared. The tube then appeared to he filled with a homogenous substance, neither gaseous nor liquid; apparently a new state of matter. When the temperature was slightly dimin ished, or the pressure relaxed, there was a singular appearance of flickering strim, such as one sees on mixing alcohol and water, or on looking through the column of irregu larly heated air rising from a hot body. No pressure that Andrews could apply, not even 400 atmospheres, could liquefy this gas when its temperature was above 88° Fahr. It appears that for every gas there is a point of temperature above which it is impossi ble by any amount of pressure to liquefy it.
The so-called permanent gases—oxygen, hydrogen, and nitrogen—have at last yielded to the patience and skill of M. Pictet of Geneva and 31. Cailletet of Paris, and have been liquefied, or even solidified. In the last months of 1877 oxygen was liquefied under a pressure of 500 atmospheres; hydrogen, when subjected to a pressure of 280 atmos pheres; and nitrogen, under a pressure of 200 atmospheres.
VAR, a department in the extreme s.e. of •France, bounded on the s. and s.e. by the Mediterranean, and on the n.e. by the department of Alpes Maritimes. See ALPES 31AurrimEs. Area. 2,348 sq.m.; pop. '76, 295,763. The department receives its name from the river Var, which formerly served as its boundary on the e., but which, since the arrondissement of Grasse was taken from the department of Var, and added to that of the Alpes Maritimes, now belongs entirely to the latter. Var is well watered by a great number of streams, of which the chief are the Gapau, Argens, and Manson. In the u. and n.e. it is mountainous, being traversed by a branch of the Alpes de Provence, called the _Monts de l'Esterel. Between the mountains and the water-courses are many very fertile valleys. The climate of Var, tempered by the altitude of the surface, is pleasant. Fruits of all kinds are here cultivated with remarkable success; tobacco is grown, and 17,600,000 gallons of wine are produced annually. The department abounds in minerals: an active commerce is carried on, the exports being chiefly wine, fruits, olive-oil, and other agricultural and horticultural products. It is divided into the three arrondissements of Draguignan, Brignoles, and Toulon. Capital, Draguignan.