212 Dr. Maton's and Mr. Rackett's 



MR. HATCH ETT 



is the only author, with whose writings we are acquainted, that has 

 scientifically investigated what may be called the chemical cha- 

 racters of shells; a comparison of which with those derived from 

 external structure cannot but be highly curious and interesting to 

 the philosophical naturalist. To the disciple of Linnaeus it is 

 peculiarly satisfactory to perceive that so many of Mr. Hatchett's 

 experiments tend to establish the propriety of distinctions adopted 

 by that illustrious naturalist. We would only refer the reader to 

 the instance of the Echinus, the chemical characteristic of which 

 genus proves, in opposition to Klein, the correctness of Linnaeus, 

 in placing it among the crustaceous instead of the testaceous 

 tribe ; the presence of the phosphate of lime detected in the cover- 

 ing of the Echinus distinguishes the latter from testaceous sub- 

 stances, which consist only of carbonate of lime mixed Avith the 

 gelatinous matter. When one science can thus be made to remove 

 unavoidable ambiguities in another, a beautiful example is esta- 

 blished of the intimate connection that subsists between all the 

 various branches of natural knowledge. 

 In the year 1799 



MR. DONOVAN 



began the publication of the Natural History of the British Shells, 

 including figures and descriptions of all the species hither- 

 to discovered in Great Britain, systematically arranged in the 

 Linnean manner, with scientific and general observations on 

 each. Of this work five volumes in octavo have appeared, com- 

 prising 180 plates, with coloured figures ; but, as it is not yet 

 completed, we have only to observe, that the author has given 

 several new species, and that he has rectified many errors of pre- 

 ceding writers. 



The 



