42 



MURIATIC AND OXYMURIATIC ACIDS. 



in contact with the substance they embraced, were compressed 

 and flattened. 

 The tendrils The actions of the tendrils of the pea were so perfectly 



affecteTas "" similar to tllose °f tne vine » wnen lne > r came into contact w hh 

 those of the any body, that I need not trouble you with the observations I 

 * me * made upon that plant. An increased extension of the cellular 



substance of the bark upon one side of the tendrils, and a cor- 

 respondent contraction upon the opposite side, occasioned by 

 the operation of light, or the partial pressure of a body in 

 contact, appeared in every case which has come under my 

 observation, the obvious cause of the motions of tendrils ; and 

 therefore, in conformity with the conclusions I drew in my last 

 memoir, respecting the growth of roots, I shall venture to infer, 

 that they are the result of pure necessity only, uninfluenced 

 by any degrees of sensation, or intellectual powers. 



T. A. KNIGHT. 

 Doivnton, April 2J ', 1812. 



IX. 



Introductory 

 remarks. 



Reference to 

 the contro- 

 versy between 

 Mr. Murray 

 and Mr. John 

 Davy. 



Additional Experiments on the Muriatic and Oxy muriatic Acids. 

 By William Henry, M. D. F. R. S. V. P. of the Lit. and 

 Phil, Society, and Physician to the Infirmary at Manchester. 

 From the Philosophical Transactions, 1812. 



THE experiments, which form the subject of the following 

 pages, are intended as supplementary to a more extensive 

 series, which the Royal Society did me the honour to insert in 

 their Transactions for the year 1800*. Of the general accu- 

 racy of those experiments, I have since had no reason to 

 doubt ; and their results, indeed, are coincident with those of 

 subsequent writers of the highest authority in chemistry. My 

 attention has been again drawn to the subject by the impor- 

 tant controversy which has lately been carried on between Mr. 

 Murray and Mr John Davy, respecting the nature of mu- 

 riatic and oxymuriatic acidsf ; and I have been induced, by 

 some hints which the discussion has suggested, not only to 



* Page 188. f Nicholson's Journal, XXVIII, and XXIX. 



repeat 



