LAUGEL'S PROBLEMS OF NATURE AND LIFE. 333 



morphology can be constructed to meet all the condi- 

 tions of the problem ? Nearly seventy kinds of matter 

 are still elementary to our knowledge. Are we to sup- 

 pose different figures of the component atoms of each 

 of these ? Or in sight of this difficulty, may we pre- 

 sume that many of them are really compounds of 

 simpler elements, though beyond the reach of discovery 

 as such ? or allotropic conditions of the same element, 

 as Dumas conjectures regarding chlorine, iodine, and 

 bromine ? Questions still more intricate offer them- 

 selves when we come to the molecular compounds of 

 atoms. Here we are almost compelled, on physical 

 conditions, to suppose a variety of configurations as 

 great as the diversity of properties which these mole- 

 cules exhibit, and which are in no way more curiously 

 exhibited than in their various action on the animal 

 economy. A slight difference in the proportions even 

 of the same ingredients in a compound makes the dif- 

 ference between a food and a poison. Professor Tyn- 

 dall's experiments on the transmission of radiant heat 

 through gases have already furnished conclusions of 

 great interest to our knowledge of molecular physics. 

 We would willingly look to his labours and genius for 

 further exploration in this field of research. 



In close connexion with these questions we must 

 refer to another new method of analysis the growth, it 

 may be said, of our own time. We allude to the ad- 

 mirable researches of the late Master of the Mint, 

 whose death (following soon after that of a still more 

 illustrious philosopher) we have much cause to deplore. 

 Professor Graham, in devoting his long labours to the 



