Chemical Science. \ 205 



that if the sun shone upon the substances when the action was 

 nearly complete, each bubble of chlorine as it entered the alcohol 

 produced a brig-ht purple iiame, a dense white vapour, and caused 

 violent concussions in the liquid; another curious instance, in addi- 

 tion to the many that are known, of the power of solar ligiit over 

 chemical action. — Journ, de Pharm. 1826, p. 627'4:jLrfs.B)3 < 



11. Test for the Presence of Nitric Acid. — The following method 

 is one devised by Dr. Liebi^, for the detection of this substance, 

 which it will effect, he says, when there is not more than a four- 

 hundredth part of the acid present. The liquid to be examined 

 must be mixed with sufficient sulphuric solution of indig-o to acquire 

 a distinct blue colour, a few drops of sulphuric acid added, and the 

 whole boiled. If the liquid contains a nitrate, it will be bleached, 

 or, if the quantity is very small, rendered yellow. By adding' a 

 little muriate of soda to the liquid before applying heat, a five- 

 hundredth of nitric acid may easily be discovered. — Ann, de Chimicy 

 XXXV. 80. 



12. Peculiar Formation of Nitre. — ^The leaves and stems of beet 

 root contain oxalate and malate of potash. Some leaves were tied 

 tog-ether and hung- up in a warm and slightly-humid place, where 

 there was but little light, to dry. Being examined at the end of 

 several months, they were found penetrated with, and covered by, 

 an immense number of minute crystals of nitre. The oxalic and 

 malic acids had been replaced by nitric acid ; but whether from 

 animalized matter naturally in the leaves of the plant, or from the 

 action of the air, or in what manner, is not known. — M. Henri 

 Braconnot, Ann. de Chimie, xxxv. 260. 



13. Experiments on Fluoric Acid and Fluates, by M. Kuhlman, 

 —These experiments were made with dry sulphuric acid and fluor 

 spar, with the intention of proving that fluor spar is truly a com- 

 pound of fluorine and calcium, and not of fluoric acid and oxide 

 of calcium. A quantity of anhydrous sulphuric acid was prepared 

 with great care, and collected in a glass tube ; the latter was then 

 connected with a platina tube charged with fluor spar, which had 

 previously been calcined in a platina crucible, and a glass tube was 

 connected with the other end of the platina tube for the purpose of 

 conducting and facilitating the collection of the gas evolved over 

 mercury. The fluor spar was heated to redness, and then the tem- 

 perature of the sulphuric acid raised so as to cause a stream of it 

 in vapour to pass over the fluor spar ; but there was not the sHghtest 

 reaction, the sulphuric acid recondensed in part in the farthest tube, 

 and no trace of fluoric acid was produced. Dry sulphuric acid was 

 then put, in the liquid state, in contact with dry fluor spar, but 

 there was no decomposition, and no portion of the spar was con- 



