190 ANALYSIS OF BRITISH AND FOItElCN SALT. 



moving the linchpin <*, when the wheel is to be takeu off; 

 but if the linchpin a should accidentally get out, this addi- 

 tional pin b would effectually keep the wheel on, as its hang* 

 in-- position docs not at all tend to shut the pin up into the 

 axle, but the contrary. The common linchpin a is put in 

 downwards, and its weight may also tend to keep it in, anil 

 is secured in the usual way by a strap, the holes for which 

 may be seen in the figures. The whole, when iu its place, 

 is shown at fig. 4. 



VIII. 



An Analysis of several Varieties of British and Foreign Salt 

 {Muriate of Soda J, with a view to explain their Fitness for 

 different economical Purposes. By William Henry, 

 M. D. F. P. S. V. P. of the Lit. and Phil. Society, and 

 Physician to the Infirmary at Manchester*. 



Sect. I. General Observations. 



Ofcjeet of the 



JiN undertaking the series of experiments, described in the 

 following pages, I had not so much in view the discovery of 

 novelties in science, as the determination, by the careful em- 

 ployment of known processes, and by the improvement of 

 methods of analysis, of a number of facts, the establish- 

 ment of which (it appeared to me probable) might have an 

 influence on an important branch of national revenue and 

 industry. 

 Bfitis. salt An opinion has for some time past existed, and I believe 



general Ty con- na& been pretty general both in this and other countries, to 

 Brdercd of inte- , , r ,. T> . • , lx ,. . 



nor quuiity. the disadvantage ot British salt as a preserver or animal 



food ; and a decided preference has been given to the salt 

 procured from France, Spain, Portugal, and other warm 

 climates, where it is prepared by the spontaneous evapora- 

 tion of sea water. In conformity with this opinion, large 

 sums of money are annually paid to foreign nations, for the 

 supply of an article, which Great Britain possesses, beyond 



* Philosophical Tiansaction^for I8t0, Part I. 



almost 



