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equilibrium lunar tide in a solid glass globe (without mutual 

 gravitation) of the same size as the earth is about five feet. 

 Hence, from the phenomena of the actual tides of the ocean, 

 it follows that the earth, as a whole, is more rigid than glass. 

 The observations of Mallet, with experimental earthquakes, 

 show that the earth's crust is many times less rigid than glass. 

 Hence Professor Thomson infers that the earth, as a whole, 

 is many times more rigid than the rocks and strata on its 

 surface. 



Dr. Grace Calvert stated that he wished to draw the 

 attention of the manufacturing chemists of this district to a 

 very simple and rapid method which had been devised by the 

 eminent chemist M. Pelouze, Master of the Paris Mint, for 

 determining the amount of sulphur existing in pyrites. He 

 (Dr. Calvert) was induced to do so, believing that any pro- 

 cess which would simplify the long and troublesome operations 

 now followed to ascertain the value of this mineral would be 

 useful to many members now present at this meeting. The 

 process consists in mixing intimately together one part of 

 pyrites, thoroughly pulverised in an agate mortar, with five 

 parts of carbonate of soda, seven parts of chlorate of potass, 

 and five parts of chloride of sodium, and placing the whole in 

 an iron spoon, which is gradually carried to a dull red heat. 

 The mass, when cold, is first washed with cold water and 

 then with boiling water, until the whole of the soluble matter 

 is removed ; and this solution is tested with a standard solution 

 of sulphuric acid. As 100 grains of carbonate of soda requires 

 92*45 of monohydrated sulphuric acid, or S O3 H O, it follows 

 that the quantity of soda in the carbonate of soda employed 



