614 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



opportune for the introduction of the metrical system ; that 

 all spun material should, if possible, be numbered on the same 

 principle ; that this should be metrical, and the number of 

 the yarn should express the number of meters in a gramme, 

 and that the minimum for inspection should be 1000 meters. 

 The establishment of a uniform reel was passed over for the 

 present. A standing committee of delegates from the coun- 

 tries represented was selected, to publish the results in their 

 respective countries, and impart strength to the new move- 

 ment. The meeting next year was fixed at Brussels. 32 C, 

 Jult/ 19, 1813,351. 



PEEPAEATION OF CAEBONATE OF MAGNESIA. 



The fact that, in the treatment of dolomite with carbonic 

 acid under pressure, the carbonate of magnesia dissolves more 

 readily than the carbonate of lime, is employed on a large 

 scale in Pattinson's process at Newcastle, England. The fine- 

 ly powdered dolomite is stirred with cold water, in a cyl- 

 inder revolving on a horizontal axis ; and carbonic acid, ob- 

 tained by the action of hydrochloric acid on carbonate of 

 lime, is forced in, under a pressure of five to six atmospheres. 

 The solution of bicarbonate of magnesia, thus obtained, is 

 treated with steam in a vertical cylinder; and the neutral 

 carbonate formed is allowed to deposit in channels, and is 

 then cut out in rectangular blocks, dried, and brought into 

 the market, affording caustic magnesia by ignition in muffles. 

 QC, July 10, 181 3,21 Q, 



