On Lime and Marh^ 209 



the profit derived from them. It would seem that the 

 circumstance of the dressing Du Hamel's marble chim- 

 ney-piece, has become the ground work of Dr. An- 

 derson's, or more properly the English, theory, con- 

 cerning calcareous substances, which has been car- 

 ried to such a length as to lose sight of the practical 

 experience of farmers. But had Du Hamel been along 

 with me, I could have shown him many instances of a 

 remarkable effect produced upon natural as well as 

 sown grasses, by the small dust, from the dressing with 

 the hammer of the hard why n- stone, of which many 

 stone dykes, or fences, are built in Scotland. This 

 has been often observed by many besides myself, and 

 could not be attributed to calcareous matter. Whe- 

 ther sulphuric acid was the active principle I shall not 

 pretend to say; but the whyn- stones, when broken, emit 

 a strong sulphuric smell. For my own part, I pro- 

 nounce nothing positive, my motive is to bring every 

 theory to the test of experiment. If these hints have 

 any effect in calling forth further investigation, my 

 object is obtained. 



If you think this worth presenting to the society, 

 you may, if you please, accompany it with your free 

 remarks. 



I am, sir, 



with great respect, 



yours, &c» 



John Lang- 

 Richard Peters, Esq^. 



VOL. III. D d 



