Process for the Preparation of Muriate of Mei cury. 28 1 



reef. Tenth. 



Multiply 91 7 by 3,6,9 = 3333,7 



Add, increasing ratio 5 per 100 ... .= 169, 



Estimated height . . 3552,7 



Height by geometrical measure 3558 feet. 



Example 4. 



Incher. Tenth Ihmi. 



Lower station 29,9,3 



Upper station 1 6,8, 1 



Difference 13,1,2 



Mean temperature of air 64- .......= 934 feet to each 



For lower station 29,9 add . , 3 inch of 



variation. 



93 7 



Multiply 937 by 13,1,2 == 12^93,4* 



Add increasing ratio 29 per 100. .= 3,565, 



Estimated height . . 15,858,4 



Height by geometrical measure ..... 1 5,S33 feet. 



N. B. In the three last examples, the heights of the ba- 

 rometer at thedifferent stations, and the geometrical heights 

 corresponding thereto, are extracted from different works 

 of unquestionable authority. I am, sir, 



Your obedient servant, 



Queen-street, Oxford, PiICHARD WALKER. 



Oct. 1.",, 1810. 



L1V. (Economical Process for the Preparation of the sub- 

 limed Muriate of Mercury {Calomel)-, to luhick is sub- 

 joined, an easy Method of purifying the Calomel used in 

 Commei-ce. By M. Planche *. 



Anxious to avoid the inconvenience which results from 

 the employment of corrosive sublimate in the preparation 

 of calomel ; convinced by experience that the various me- 

 thods proposed with this vie^v by Van Tvions and Brugnatelli 

 were insufficient; and considering the discrepancy which 

 prevails in most of the pharmacopoeias of Europe, as to the 



* Annates de Chimic, tome Ixvi. p. 168. 



