CONTRIBUTIONS TO MICRO-MINERALOGY. 279 



should be applicable, not merely to niieroseopical, but to 

 chemical and physical examinations, and that should combine 

 in one, the principles of Nachet's Ctiemical Microscope with 

 those of Soleil's Polaroscopes for the measurements of the 

 optic axes, circular polarization and saccharimetry, Daiker's 

 Selenite stage, KobelTs Stauroscope, Leeson's and WoUaston's 

 goniometers, Jackson's micrometer, with the means of deter- 

 mining the Indices of Refraction in minute crystals, vScc. 



The instruments known as Nachet's Chemical Microscope 

 since the Exhibition of 1851, and figured in the edition 

 of Professor Quekett's Treatise of that year, has been 

 claimed by Professor J. Lawrence Smith, of tlie University 

 ot Louisiana, U. S., as his invention, who seems wrath with 

 M. Nachet for not having mentioned his name in connection 

 witli the instrument, and with Professor (^uekett for not 

 knowing, wliat I believe few others knew till the appearance 

 ol his article in the Sej)tember number of Silliman's Journal 

 lor 1852, vvlierein he states that this form of instrument 

 he invented in 1850, and brought under the notice of the 

 Suciefe de Biologie^ of Paris, in the month of September of 

 that year, and with improvements in the micro-metrical parts 

 before the American Scientific Association in 1851. Those 

 who are acquainted with the wholesale way in which the MS. 

 descriptions of Exhibitors' articles were, in most cases as a 

 matter of necessity, cut down to occupy the least possible 

 space in the Official Catalogue of the Great Exhibition, will 

 not, perhaps, think M. Nachet the one to blame that Pro- 

 fessor J. L. Smith's name did not appear in connection 

 toitli the sinqle line* that records the appearance of this Micro- 

 scope at the World's Fair. Or can Professor Quekett be 

 fairly blamed, if with many calls upon his time, he does not 

 read every foreign journal that may issue from the j)rolific 

 Continental press, or that he did not become acquainted with 

 the proceedings of the American Scientific Association for 

 1851, before he issued his edition of December in that year, 

 considering that, like our own British Association, it does 

 not publish its Reports immediately after its adjournment; or 

 that he should not have known that Messrs. Wartz and Verdiel 

 had that form of instrument in use at their laboratory in 

 Paris, especially as Professor Smith states that only mention 

 was made in the Minutes of the Societies referred to, and that 

 no j)uhlished account of his principle had been given to the 

 world. 



Curiously enough I first became acquainted with this prin- 



* See Descriptive Catalogue, vol. iii., p. 1242, No. 1370 ; also Juries' 

 Reports, p. 267. 



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