Professor Jameson' s System of Mineralogij, 35 



these from their dearest friends on such trifling grounds. Why 

 not, most worthy sir? You have felt no such compunction on 

 other occasions : and give me leave to add, that if vou establish 

 characters to which yon do not adhere, they are good for nothing*. 

 We are told, in the preface, that the arrangement " is totally in- 

 depeiident of any aid from chemistry;" and again, that " the 

 chemical characters and composition of simple minerals are not 

 employed in arranging and determining the species." Yet, at the 

 close of many of the articles we have, under the head of " Ob- 

 servations,'' some of the most valuable information contained in 

 the work ; consisting in a great measure of such discriminating 

 cnaracters as will enable us to distinguish the preceding species 

 from those to which it bears the most perfect resemblance : these 

 differences are in many cases external, but yery frequently de~ 

 pend on the effect of the blow-pipe— sometimes on the action of 

 acids : thus, this perfectly independent system, although it will 

 not suffer chemical phaenomena to make part of the essential 

 characters of a mineral, resorts indirectly to chemistry for light, 

 where its own vague and indeterminate language would only lead 

 youinto a labyrinth, and leave you in the dark. One great ob- 

 jection to the external system is, that, bv allowing the characters 

 of each individual to occupy nearly or quite a page, and by in- 

 troducing shadowy distinctions, which, so far from being un- 

 derstood from mere description, can scarcely be comprehended 

 when pointed out by an instructor, it banishes all hope of being 

 able to carry any useful degree of information in the memory; 

 and leaves the determination of species to instinct, or tact. On 

 reference to the book, the mind becomes bewildered with the in- 

 definite definitions.— Look at fibrous brown zinc blende : there is 

 not a character but what is included in the more diffuse account 

 of fibrous brown iron ore. How shall we discriminate ? The lustre 

 of the latter is " intermediate between pearly and resinous." But 

 we are told that the former differs from it " principally by its re- 

 sinous lustre, and its accompanying minerals." Antimony ochre 

 also " nearly resembles bismuth glance in its external characters, 

 but IS readily distinguished from it by its accompanying inine- 

 rals. This is most sublimely scientific ; to determine a doubt- 

 ful point, not by the examination of the mineral itself, but by 

 * No one could regret more than Linnaeus that the essential characters 

 m his sexual system made U necessary for him to i)lace the Labintce with 

 two stamens in the class D)a>ulria and the Papiliomcccc witli distinct stamens 

 in Vecandrin : hut he saw too well the puerility of formin!,^ characters to be 

 adhered to only so long as was convenient : had he thought as loosely of 

 essential characters as Professor Jameson, the plants referred to would have 

 been placed without hesitation in Dldiimmm and Diadelphia. There is a very 

 wide difference between a man of real science and a mere system builder. 

 C 2 observing 



