On seme nczv analytical Researches, JSJ 



of various thickness : subsequent experiments, however, 

 proved that the slaty sch.stus uf Roule, in the environs of 

 Cherbourg, is prtterable, and that good n)ortar may be 

 made with the ferrugnious schist of Haineville, which is 

 inferior, however, to the two former. 



Atter having multiplied and varied his experiments in 

 such a manner as to present positive results, M. Lepere, 

 in conjunction with the connnittee of engineers appointed 

 to exjiriine his experuiients, draws the following conclu- 

 sions : 



1st. That the schist of Cherbourg, when strongly cal- 

 cined and pulverised, forms an excellent mortar when 

 mixed with sour lime. 



Sdlv- That in order to give precisely the same properties 

 to schist which are possessed by puzzulano and terrass, the 

 former must be calcined in a reverberating, instead of a 

 lime, furnace. 



XXVI. The Bakerian Lecfwe. An Acconnt of some new 

 analytical Researches on the Nature of certain Bodies, 

 particularly the Alkalies, Phosphortis, Sulphur, Car- 

 bonaceous Matter, and the Acids hitlierto undecomposed ; 

 ii'itli some general Observations on Chemical Theory. By 

 HuMPHPxY DAvr, Esq., Sec. R.S., F.H.S. Edin., and 

 M.R.LA. 



[Concluded from p. 124.] 



VIII. Analytical Experiments on Muriatic Acid. 



J. HAVE inade a greater number of experiments upon this 

 substance, than upon anv of the other subjects of research 

 that have been mentioned ; it will be impossible to give any 

 more than a general view of them within the limits of the 

 Bakerian lecture. 



Researches carried on some years ago, and which are 

 detailed ui the Journals of the Royal Institution, showed 

 that there were little hopes of decomposing muriatic acid, 

 in its connnon form, by Voltaic electricity. When aqueous 

 solution of muriatic acid is acted upon, the water alone is 

 decomposed ; and the Voltaic electrization of the gas affords 

 no indications of its decomposition ; and merely seems to 

 show, that this elastic fluid contains much more water than 

 has been usually suspected. 



I have already laid before the Society, an account of some 



experiments made on the action of potassium on muriatic 



M 3 acid. 



