Page:Experimental researches in chemistry and.djvu/241

226 were then heated nearly to the boiling-point, air being continually passed through. In this way all the chlorine which had combined with the carbonated alkali without decomposing it, was set free by the sulphuric acid, and carried off by the current of air and vapour, whilst any which had acted chemically upon the alkali would, after the action of the sulphuric acid, be contained in solution as muriatic and chloric acids, and from the diluted state of the whole, would not be removed by the after process, but remain to be rendered evident by tests. The other portion being diluted, had sulphuric acid added also in excess, but no attempt was made to remove the chlorine. Equal quantities of these two portions in the same state of dilution were then examined by nitrate of silver for the quantities of chlorine sensible in them, and it was found that the latter portion, or that which retained the whole of the chlorine thrown into it, contained above sixty times as much as the former.

12. Now although it may be supposed that in the former portion that part of the chlorine which, in acting energetically, had produced chloric acid, could not be detected by the nitrate of silver, yet more than a sixth of the small portion which remains cannot be thus hidden; and even that quantity is diminished by the sulphuric acid present in excess, which tends to make the chlorine in the chlorate sensible to nitrate of silver: so that the experiment shows that nearly 59 parts out of 60 of the chlorine in M. Labarraque's liquid are in a state of weak combination with the carbonated alkali, and may be separated by acids in its original condition; that this quantity is probably wholly available in the liquid when used as a bleaching or disinfecting agent; that little, if any, of the chlorine forms chloride of sodium and chlorate of soda with the alkali of the solution; and that the portion of chlorine used in preparing the substance which is brought into an inactive state, is almost insensible in quantity.

13. The peculiar nature of this compound or solution, with the results Mr. Phillips had shown me (8), obtained by evaporation of a similar preparation to dryness, induced me to try the effects of slow evaporation, crystallization, heat, and air upon it. In the first place, five equal portions of the solution prepared by myself were measured out: two were put into