96 



VIEWS OF THE MICROSCOPIC WORLD. 



Fig. 148. 



Fir. 149. 



Fig. 150. 



their identity with the coniferous woods is at once perceived. Figure 147 is a 

 transverse section of a species of Pine, petrified by flint, Fi 14? 



and taken from a quarry near Maidstone in Kent. It is 

 magnified in length one hundred and twenty times, and is 

 exhibited as it appeared when viewed by reflected light ; 

 ihe lighter portions representing the delicate web of fibres 

 constituting the wood. A longitudinal section of the same 

 wood is shown in figure 148, magnified li- 

 nearly two hundred and fifty times. Sev- 

 eral rows of parallel vessels are revealed 



running in the direction of the trunk, and each, like the White 

 Pine, is studded along the sides with 

 single rows of disks or glands. Fig- 

 ure 149 is a transverse section of co 

 riiferous wood, petrified by lime. It 

 is magnified eighty times, and exhibits very clearly 

 the cross sections of numer- 

 ous rows of transverse ves- 

 sels. Figure 150 is a lon- 

 gitudinal section of the same, magnified one hun- 

 dred and twenty times, and shows with great dis- 

 tinctness the coniferous nature of the wood, for the 

 double rows of disks alternating with each other, 

 are seen embossing the whole range of the parallel 

 vessels. Ferns of great beauty are preserved by 

 petrifaction in the same manner. In the vicinity of 

 Chemnitz in Saxony, ferns petrified by flint are found, their external surface 

 possessing a woody appearance of a reddish brown hue, while the interior struc- 

 ture is of a dull red, variegated with blue and yellow, arising from the agate and 

 chalcedony which occupies the most minute ramifications of the vessels of the 

 plant. When slices of the fossil are ground down very thin, the microscope re- 

 veals the peculiar structure of the plant, though unnumbered years have elapsed 

 since it was living, with as much faithfulness as the organization of the speci- 

 men which has just been gathered from the fields. 



Not only are the more solid and durable portions of wood and vegetables 

 preserved for ages by petrifaction, but the pollen of cone-bearing trees, like the 

 Pine, has been found in a fossil state. In Egra, in Bohemia, a deposit has been 

 discovered two miles long and twenty-eight feet thick, entirely composed of/os- 

 sil animalcules and pollen ; the first ten feet being marl filled with Infusoria, 

 and the remaining eighteen, pollen mingled with fossil animalcules. 



COAL. It has been proved beyond a doubt that the vast stores of coal, which 

 have been provided for the use of man, are of vegetable origin ; and the micro- 

 scope has been of essential use in enabling the investigator to detect the peculiai 



