"ouCat Zch^?m] Rotjcd Microscopical Society. 123 



to some of his criticisms. It is true, for instance, that alcohol 

 alone is not the best menstruum for the chlorophyll of plants. A 

 previous aqueous solution is desu'able. Of this I have just had a 

 striking example when examining the spectrum of the Japan honey- 

 suckle. The dark purple skin of the fruit yields a pui-ple solution 

 to water, and its spectrum is marked by the obliteration of the red, 

 with the exception of a curiously thin bright band untouched in 

 the middle of the red, — the obliteration of the yellow and blue, and 

 the exaltation of the green. The subsequent alcoholic solution of 

 the portion first acted on by water gives a green solution of chloro- 

 phyll, and its spectrum is now characterized by a magnificent black 

 band near the commencement of the red, over the line B, — a pale 

 band in the green, and the cutting off of nearly all the blue. 

 Whereas the spectrum of a primary alcoholic solution is a curious 

 mixture of these two spectra. 



Another striking example of the accuracy of spectroscope work 

 was lately supplied by Mr. Sorby, to whom I forwarded the dichroic 

 fluid exhibited at our last Sou-ee. Mr. Sorby clearly proves that a 

 very different spectrum is produced by the addition of albumen to 

 the confervoid mass, and hereby he establishes Mr. Sheppard's con- 

 clusions, and disestablishes Mr. Eay Lankester's assertions. 



Mr, Browning's micro-spectroscope was lately added to our 

 Eoss-microscope. The spectroscope leads us into a new field of 

 research, and the wonders revealed by this marvellous instrument 

 are only dawning upon us. Ah-eady it converts the telescope into 

 a celestial microscope, and in the hands of our distinguished Fellow, 

 Mr. Huggins, now on the Council of the Koyal Society, it enables 

 him to deal with the constituents of some of the mighty spheres of 

 the universe as if they were merely elements of the Volvox globaior. 

 Mr. Browning has recently improved the series of prisms, and also, 

 in order to secure a reliable measurement of absorption bands, he 

 has converted the instrument into a micromeier-spedroscope ; and 

 I have the pleasure of stating that Mr. Browning wiU put new and 

 more powerful prisms to our own instrument, and will also add 

 " the new measuring apparatus " as a present to the Society. Mr. 

 Browning's communication on this subject was read at our last 

 meeting, and we learn from it, in few words, that the micrometer- 

 spectroscope determines the j)osition of absorption bands by their 

 accurately measured distance from Fraiinhofer's fixed lines of the 

 spectrum, while the ordinary micro-spectroscope determines their 

 position by their distance fi-om one of Mr. Sorby 's 12 interference 

 lines produced by a thin plate of quartz between two Nicol's 

 prisms. Mr. Sorby's ingenious artificial scale is thus superseded 

 by an unalterable natural scale. 



With respect to the attempts brought before us to improve the 

 microscope itself as an instrument of scientific research, I must 



