42 Things not generally Known. 



THE MICROSCOPE AND THE SEA. 



What myriads has the microscope revealed to us of the rich 

 luxuriance of animal life in the ocean, and conveyed to our as- 

 tonished senses a consciousness of the universality of life ! In 

 the oceanic depths every stratum of water is animated, and 

 swarms with countless hosts of small luminiferous animalcules, 

 mammaria, Crustacea, peridinea, and circling nereides, which, 

 when attracted to the surface by peculiar meteorological condi- 

 tions, convert every wave into a foaming band of flashing light. 



USE OF THE MICROSCOPE TO MINERALOGISTS. 



M. Dufour has shown that an imponderable quantity of a 

 substance can be crystallised ; and that the crystals so obtained 

 are quite characteristic of the substances, as of sugar, chloride 

 of sodium, arsenic, and mercury. This process may be ex- 

 tremely valuable to the mineralogist and toxicologist when the 

 substance for examination is too small to be submitted to tests. 

 By aid of the microscope, also, shells are measured to the thou- 

 sandth part of an inch. 



FIXE DOWN OF QUARTZ. 



Sir David Brewster having broken in two a crystal of quartz 

 of a smoky colour, found both surfaces of the fracture abso- 

 lutely black ; and the blackness appeared at first sight to be 

 owing to a thin h'lm of opaque matter which had insinuated 

 itself into the crevice. This opinion, however, was untenable, 

 as every part of the surface was black, and the two halves of the 

 crystals could not have stuck together had the crevice extended 

 across the whole section. Upon further examination Sir David 

 found that the surface was perfectly transparent by transmitted 

 light, and that the blackness of the surfaces arose from their 

 being entirely composed of a fine down of quartz, or of short 

 and slender filaments, whose diameter was so exceedingly small 

 that they were incapable of reflecting a single ray of the strong- 

 est light ; and they could not exceed the one third of the mil- 

 lionth part of an inch This curious specimen is in the cabinet 

 of her grace the Duchess of Gordon. 



MICROSCOPIC WRITING. 



Professor Kelland has shown, in Paris, on a spot no larger 

 than the head of a small pin, by means of powerful microscopes, 

 several specimens of distinct and beautiful writing, one of them 

 containing the whole of the Lord's Prayer written within this 

 minute compass. In reference to this, two remarkable facts in 

 Layard's latest work on Nineveh show that the national records 

 of Assyria were written on square bricks, in characters so small 

 as scarcely to be legible without a microscope ; in fact, a micro- 

 scope, as we have just shown, was found in the ruins of Mmroud. 



