S4 General Remarks 



or about 100 of oil of vitriol, and will yield 246 pounds of 

 crystallized Epsom salt. The carbonate of magnesia or magnesia 

 alba of the shops is made by decomposing a solution of the sul- 

 phate with a boiling solution of carbonate of potash or soda.- 

 The carbonate of magnesia separates as a white powder, which 

 is washed with water, pressed into cubes and dried. It contains 

 about 40 per cent, of magnesia combined with variable propor- 

 tions of carbonic acid and water. These are dried off, when the 

 magnesia alba is heated to redness, and caustic or calcined magne- 

 sia remains. Serpentine will thus yield about its own weight of 

 the carbonate and 40 per cent, of calcined magnesia. 



There are other sources of magnesia in the dolomites and mag- 

 nesites of the country, but a description of these and of some of 

 the uses of magnesia in the arts, we shall reserve for another 



number of the Canadian Naturalist. 



T. S. H. 



ARTICLE V. — General Remarks on the Study of Nature, with 

 special reference to Botany, 



It will be acknowledged by every student of nature, that much 

 pleasure and gratification are experienced in the general contem- 

 plation of the works of Creation. However cursory his observa- 

 tions may be, they exercise a wholesome influence upon the mind, 

 excite admiration within the breast and encircle the imagination 

 with a halo of pleasurable feelings. It is within the compass of 

 every mind, however crudely educated, to receive such genei*al 

 impressions, and to benefit by the display of those objects of nature 

 which ever prove sources of recreation. A recognition of this has 

 led to the adoption, more especially in large towns, of extensive 

 Parks and Botanic Gardens, which, as places of general resort, 

 tend materially to the physical and mental improvement of popu- 

 lous communities. It must be remembered, however, that the 

 mere general contemplation of the works of the Creator is not all 

 that is required of man, to whom was given poiuer, to have com- 

 mand over " things possessing life," and intelligence,io study with 

 advantage to himself the numerous and varied objects placed before 

 him. Nor must we be satisfied with a mere cursory glance of the 



