As Berzelius found 100 parts of fluor spar, when acted upon by sulphuric acid, to yield 175 parts of sulphate of lime, equal to 73.553 parts of lime, or 52.819 of calcium, it follows that 100 parts of fluoride of calcium should contain 47.181 of fluorine and 52.819 of calcium. By the assistance of this result, and further experiments, M. Kuhlman proceeded to ascertain the composition of hydro-fluoric acid. Dry muriatic acid gas was passed over calcined fluor spar heated to redness in a tube of platina; the fluoride of calcium was decomposed, free hydro-fluoric acid was evolved, and chloride of lime remained in the tube. The hydro-fluoric acid acted upon the glass tubes, but being received in water was entirely dissolved, with the exception of the silica it had separated from the glass: no trace of hydrogen appeared. One hundred parts of fluoride of calcium thus treated became 143.417 parts of chloride of calcium, the 52.819 parts of calcium having united to 90.598 parts of chlorine. But this latter quantity must have liberated 2.511 parts of hydrogen, which must, therefore, have combined with the 47.181 parts of fluorine in the spar, to form 49.692 parts of hydro-fluoric acid. This latter body, therefore, consists of 94.941 fluorine, and 5.059 of hydrogen per cent. A small quantity of chlorine was set at liberty during the experiment, the author thinks, from a little manganese in the fluor spar. M. Kuhlman found that all the chlorides, when subjected to the action of anhydrous sulphuric acid in vapour, resisted decomposition, except the chloride of sodium, which gave a small quantity of sulphate of soda, and a double salt of soda and platina, crystallizing in fine needles of a yellow colour. No doubt is entertained that, in the latter case, the common salt and sulphuric acid were not perfectly dry.—_Bull. Univ._ 14. _Crystallization of Phosphorous_.—By the fusion and careful refrigeration of a large quantity of phosphorus, M. Frantween has obtained very fine crystals of an octoedral form, and as large in size as a cherry-stone.