PROGRESS OF MICROSCOPICAL SCIENCE. 269 



posed. On examining these objects it was found that each of the little 

 rounded disks exhibited three ridges that radiated in a triangular 

 manner from a common centre. These disks were originally masses 

 of protoplasm, lodged within a mother-cell. By-and-by each of these 

 masses broke up into three or four parts ; and it was found that to 

 accommodate one another in the interior of their circular chamber 

 they mutiially pressed one another. To illustrate the mutual com- 

 pression, Professor Williamson produced a turnip, which he had cut 

 into four parts, that corresponded exactly, he said, in their arrange- 

 ment with the arrangement of the four spores in the interior of the 

 mother-cell. 



Then Professor Huxley held that coal consisted of two elements. 

 Professor Williamson, exhibiting again a piece of coal, said the dirty 

 blackening surface was a thin layer of little fragments of woody 

 structures, vegetable tissues of various kinds, known by the name of 

 mineral charcoal. These layers of mineral charcoal were exceedingly 

 numerous. Professor Huxley, recognizing the abimdance and signifi- 

 cance of these little spore-like bodies, thought that mineral charcoal 

 formed only a portion, and a limited portion, while the great bulk of 

 black coaly matter was really a mass of carbon derived from chemically- 

 altered spores. He thought that on this point they would be obliged 

 somewhat to differ from Professor Huxley. 



The bed which had been most widely quoted as containing most 

 beautiful spores was found in the district of Bradford. If everythinof 

 decayed, and Bradford was by an exceedingly imjjrobable combination 

 of circumstances to pass out of memory, it would be remembered in 

 scientific history as the locality in which the " better bed " was found. 

 The fragment he held in his hand was a fragment of the better bed. 

 On examining it for a moment through a magnifying glass he saw that 

 it was a solid mass of mineral charcoal, yet the microscope revealed in 

 it no trace whatever of organic structure. Therefore, while Professor 

 Huxley divided coal into two elements — mineral charcoal and coal 

 proper, including in the latter term altered spores — he would say that 

 coal consisted of three elements — mineral charcoal, black coal derived 

 from mineral charcoal, and spores. 



This outline of the history of coal led them to the independent 

 conclusion that two elements were mingled in coal ; the vegetable 

 debris, or broken-up fragments, of the plants of the carboniferous age 

 were intermingled with the pecixliar spores to which Professor Huxley 

 had so properly called attention. In proceeding to deal fm'ther with 

 the plants of which coal was formed, the lecturer took occasion to 

 acknowledge with thanks the loan of certain valuable specimens, to 

 illustrate his discourse, from the Bradford Museum. One of these speci- 

 mens was a most rare and valuable sj^ecimen, which he woiild be glad 

 to take away with him to Owen's College, if he had the chance ; but 

 he was afraid the Bradford people were too conservative to stand that. 



After giving a number of botanical and other details with regard 

 to the plants of which coal was formed, he said our knowledge of this 

 subject resolved itself into two divisions, viz. that of the outward forms 

 of plants, and that of their inward organization. These two lines of 



