588 



SUPPLEMENT. 



infinite power, wisdom, and goodness of na- 

 ture's Almighty Parent." 1 



At the period when Goldsmith wrote, the 

 microscope had certainly been long in use, 

 and allusion is made in his Natural History 

 to some of the interesting facts it had then 

 made known. When, however, we consider 

 the inefficient construction of the instrument, 

 the consequent unsatisfactory results of many 

 observations, and the prevailing tendency to 

 exaggerate the discoveries of that day, we are 

 at no loss to comprehend the reason why our 

 author lays comparatively little stress on mi- 

 croscopic inquiry. Subsequent editions of the 

 Natural History have, it is true, supplied in 

 a good measure this deficiency in the original 

 work, and presented to the popular view a 

 large amount of discoveries in the minute 

 world; this information, however, has usually 

 been conveyed in a desultory form, ill cal- 

 culated to impress upon the rnind the vast 

 accessions of knowledge progressively derived 

 from microscopic investigation. The attention 

 which has, in late years, been given to the 

 construction of the microscope and the im- 

 provement of its elements, has given a new 

 impulse to inquiry, and led to the elucidation 

 of facts so astonishing, and to the discovery of 

 formations and phenomena so replete with 

 interest to the natural historian, that a new 

 edition of Goldsmith's work could scarcely be 

 deemed complete if it did not include a con- 

 nected view of the most remarkable discoveries 

 that have been made in the various kingdoms 

 of nature by the aid of optical science. This 

 digest we propose to give in three consecutive 

 chapters, dividing the subject as follows: 



CHAP. I. The results of microscopical in- 

 quiry concerning the minute formations and 

 phenomena of the natural world. 



CHAP. II. Infusorial Animalcules. 



('HAP. III. Spermatic Animalcules. 



CHAP. I. 



THE RESULTS OF MICROSCOPICAL, INQUIRY 



CONCERNING THE MINUTE FORMATIONS 



AND PHENOMENA OF THE 



NATURAL WORLD. 



MICROSCOPIC investigation has been carried 

 to a greater or less extent through all the 

 kingdoms of nature. We shall, for the sake 

 of orderly arrangement, commence with the 

 Mineral Kingdom, the discoveries in which, 

 though less diversified, are equally interesting 

 with those in the animal and vegetable 



article Microscope, iu the Supplement to the 

 Encyclopedia. 



worlds. In this division of the subject our 

 attention is more particularly called to the 

 remarkable phenomena connected with con- 

 gelation and crystallization, to the formation 

 of minute mineral bodies, and to fossil remains 

 of insects, animalcules, and vegetables. We 

 shall first advert to the singular appearances 

 presented in the congelation of water and 

 snow crystals ; for though these cannot be in- 

 cluded amongst mineral bodies, they can be 

 more conveniently reviewed in this place than 

 in any other department of our essay. 



If water be exposed to a freezing atmos- 

 phere in a capacious vessel, thin laminae, or 

 plates, of ice will shortly be observed on its 

 surface. These cross and intersect each other 

 in a most surprising manner, and present the 

 appearance of a fancifully tesselated device. 

 If one of these plates be separated from the 

 rest with a knife and brought under the mi- 

 croscope, a moderate power will develope its 

 conformation, which much resembles that of 

 a herring bone: a large stem runs through 

 the centre, and from each side of this diverge 

 a number of parallel spines, inclined to the 

 central stem in an angle of about sixty 

 degrees. In the Micrographia of Dr Hooke 

 notice is taken of a peculiarity in the congela- 

 tion of water thinly spread on smooth marble, 

 which is said to exhibit a variety of figures 

 resembling feathers ; these forms are however 

 nearly allied to the plates before mentioned, and 

 the points of difference between them are not 

 particularly remarkable. Urine when slightly 

 frozen discovers a number of very beautiful six- 

 branched figures ; but as the same formations, 

 or others very closely resembling them, may 

 be observed in a congelation of common salt 

 and water, we prefer directing our remarks to 

 the latter. These star-like figures commence 

 at the centre, which elevates itself, and ulti- 

 mately forms the apex of a solid angle ; from 

 the centre six branches jut out, each two in- 

 closing an angle of sixty degrees ; from these 

 main branches proceed a number of smaller 

 shoots, all on the same side of the branch being 

 parallel to each other, and forming with it an 

 angle of sixty degrees ; from these shoots issue 

 forth smaller branchings in like manner, and 

 from these latter others still more minute, till 

 at length the figure becomes too complicate 

 to be analysed, and presents merely the ap- 

 pearance of an even mass of ice. It is how- 

 ever to be observed, that the beauty of these 

 stars is greatly enhanced by accidental cir- 

 cumstances, which disturb the regular process 

 of congelation, and cause the branches at times 

 to throw out a number of circular plates curi- 

 ously overlapping each other. It may be 

 necessary to add that these figures differ ma- 

 terially from those observed in the ordinary 

 crystallization of common salt by evaporation. 





