62 THE BEGINNINGS OF LIFE. 



are strikingly like the forms exhibited by the simplest 

 organisms. They seem to increase in size, however, 

 by a very remarkable process of c coalescence/ all the 



cP 



' 



FIG. 40. 



Globular Carbonate of Lime. (Rainey.) 



a. Earliest forms assumed. 



b. Larger globules showing different stages of coalescence, (x 450.) 



steps of which have been fully described by Mr. Rainey. 

 He gives an account of the process by which lamination 

 takes place, and also describes the mode in which two 

 or three of these calculi, coming into contact, will gra- 

 dually fuse by a process of molecular rearrangement 



perfect and beautiful. But muriate of magnesia when decomposed in 

 the same manner and under precisely the same conditions, does not 

 furnish globules, but crystals of carbonate of magnesia, evincing no 

 tendency to become globular.' These various bodies have different 

 atomic weights, and this, doubtless, has much to do with the difference 

 of result. The atomic weights of the four are as follows : Barium 137, 

 strontium 87'5, calcium 40, and magnesium 24. That magnesium is too 

 light to enter well into combination with the gum is rendered all the 

 more probable by the fact that the effects with strontia are even better 

 than those with lime. 



