and the Emstence ofacthe Molecules in Minerals. % 



four pages contain his discovery of the action of the pollen of 

 plants when placed in water. This action, he says, " had 

 escaped the observation of all naturalists till that time, as ap- 

 pears by their express assertions ; for they affirm that water 

 causes no alteration in the farina." His observations appear 

 to have been made in the warm climate of Portugal, where 

 the action of the pollen was vigorous and rapid. Mr. Need- 

 ham says, " The farina of the jLilium flore reflexo was the 

 first in which I discovered the action of the globules ; for, 

 upon viewing it in water, I thought I perceived some alteration 

 in these minute bodies, as if the shell, or case, had emitted 

 through a small aperture a train of minute globules, which 

 appeared but as points in the microscope, involved in a filmy 

 substance, as the eggs of some aquatic insects are, and, in 

 effect, not much unlike them. I immediately applied some 

 fresh farina ; and having first fitted the microscope to a due 

 focal distance, I dropped, with the tip of a pencil, a quantity 

 of water upon the object ; when, in the course of some few 

 seconds, I distinctly perceived a train of globules, involved in 

 a filmy substance, to be ejaculated from within these minute 

 bodies, and contorting itself from one side to the other during 

 the time of action, which does not last above a second or two 

 of time, and may be easily understood by a view of Jigs. 1. 

 and 2. The drawings were taken from the pollen of the 

 mallow. The several species of farina differ but httle from 

 each other in this particular, their action in general resem- 

 bling that of an eolipile violently heated. I have since 

 repeated this experiment upon almost every species of farina 

 with the like success, particularly upon that of the pumpion, 

 which afforded me a more than ordinary gratification, not 

 only because the globules are larger than those of the farina 

 of most flowers, and may be observed with the second mag- 

 nifier, where I had the advantage of a large field, but also 

 because I could plainly perceive by two or three lucid specks, 

 which continually shifted their places during the time of action, 

 an intestine commotion within the globules, and a stronger 

 ejaculation of the emitted particles." He farther observed, 

 " that some species of farina act with so much force, that, 

 when two globules are contiguous, the action of the ejaculated 

 substance in one will repel the other to the distance of six or 

 seven times its diameter." Where the pollen was transparent, 

 he could not perceive particles in the matter ejected, which 

 appeared like a thin pellucid vapour ; of which he cites the 

 pollen of the Nasturtium as affording an instance. Mr. Need- 

 ham made use of the reflecting microscope, and the above 

 account will show that he obtained a correct view of his 



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