312 Experiments relative to Coals and Cokes 



100 parts of oxide of the following substances from [be 

 vegetable kingdom have been found thus alloyed; 



Oxides. 



Ashes. 

 - - 3*052 



Oxides. 





Ashes. 



Walnut, 



Norway Pine, 



- 



1-821 



Elm, 



- 3-300 



Chestnut, 



- 



1-800 



Holly, 



- 5'84S 



Laburnum, 



- 



4-SOQ 



Scotch Pine, 



- 2- 900 



Oak, 



- 



1-865 



Beech, 



- 4*800 



Ash, 



- 



4-273 



American Maple, 



- 3-80O 



Birch, 



- 



10-309 



Ma ho gam , 



- 3-846 



Sycamore, 



- 



5-406 



Sallow, 



- 6-135 



Lime, 



- 



3-679 



American Black Beech, 4*831 



Pit-coal affords, after burning or distillation, a lavge por- 

 tion of coke or oxide of carbon. This, in like manner with 

 that procured from wood, contains various proportions of 

 alloy. 



The coals found in the extensive coal country around 

 Glasgow are divided into five workable measures, No. 1, 2, 

 3,4,5. These are possessed of various local names, and 

 their analyses in different places give different" results Even 

 the same measure always contains two and not unfrequently 

 four different qualities, possessed of parts dissimilarly com- 

 pounded, and yielding different products when used as agents 

 in experiments. Under such circumstances, a classification of 

 these various qualities will serve better than an enumeration 

 of every particular measure, to convey an idea how these 

 oxides are compounded. 



The Scotch coals in general, in that quarter, may be short- 

 ly arranged under soft, mixed, and hard coals. 



Trre soft may again be divided into free coal, i. e. coal 

 that burns in the fire without welding or caking; and into 

 coal that in burning adheres more or less together, or that 

 enters into a bituminous kind of fusion and forms a firrn 

 compact cinder. 



Each of these varieties again yields a quantity of ashes, 

 which in colour may proceed from pure white to deep brown- 

 ish red. This distinction is of the utmost importance, 

 and Dught to be the subject of another division. So that in 

 order to form, a correct idea of the nature of the resulting 



oxide 



