02 BRAMBLES AND BAY LEAVES. 



are formed ; so also, without a supply of common salt, which is a 

 compound of a brilliant metal and a poisonous gas, the alkaline cha- 

 racter of the blood could not be maintained, and the frame would 

 soon fall into corruption and perish ; and in like manner, without 

 iron, the identical metal of which ploughshares and steam-engines are 

 formed, life could not be sustained even for the shortest space of time ; 

 for, by the presence of the metal in the globules of the blood, that 

 fluid maintains its brilliancy of colour, and is enabled to take up the 

 vitalizing atoms of the air, and so continue the enjoyments of a happy 

 existence. While still more wonderful, perhaps, are those discoveries 

 by which Liebig has rendered himself immortal, and which reveal to 

 us the chemical phenomena involved in the operations of the brain, 

 and which indicate that the amount of phosphorus and nitrogenous 

 principles, removed continually from the nervous system, are in direct 

 proportion to the intensity and continuance of thought, and which 

 point to the immediate relation of the material to the spiritual. 



Passing from these things to matters less directly associated with 

 the phenomena of life, we find beauty still predominant, and poetry 

 of the most lofty character the presiding idea. A dark surface 

 absorbs more heat than a light one ; at the same time it radiates or 

 parts with heat more rapidly than a light surface. The chemist ex- 

 poses the backs of his hands to the noonday sun ; the one bare, and 

 the other covered with a black cloth. The uncovered hand will be at 

 a temperature of from 85 to 90 degrees, and the covered one at from 

 98 to 106 degrees. The black colour absorbs about 15 per cent, more 

 heat than the white one, and yet the covered hand is uninjured, while 

 the other is scorched and blistered ; in this way, although apparently 

 in opposition to the result required, has God provided for his children, 

 who dwell under the fierce heat of the southern sun. He has made 

 them black, that they may live in harmony with the golden sunshine 

 above them, and not as the objects of the white man's tyranny, when 

 he forgets his God, and darkens the green wilderness with the shadow 

 of a devil. 



There is poetry in such facts as these ; and when the human mind 

 has achieved for itself a nobler inheritance of wisdom than it now 

 possesses, and true genius takes the place of commercial craft, we 

 shall find the poet and the painter combining to do honour to the 

 men by whose labours these wonderfiil truths have been unfolded. 

 The picture of Faraday turning a ray of light from its course by the 



