The Spectroscope and the Microscope. 301 



Before leaving this neighbourhood, it may be well to remind 

 any of our readers who may not be acquainted with that emi- 

 nently beautiful cluster, 1 5 M, that it lies at only a short distance, 

 and may be readily found by means of S Equulei and e Pegasi, 

 as will appear by the diagram. It has been described as No. 22 

 of our list, Vol. vi. p. 118. 



OCCULTATTONS. 



Nov. 4th, S 2 Tauri, 6-mag., 9h. 58m. to lOh. 37m. 5th, 115 

 Tauri, 5|-mag., lOh. 8m. to llh. 8m. 28th, B. A. C. 221, 

 6-mag., 6h. 11m. to 7h. 16'm. 



THE SPECTROSCOPE AND THE MICROSCOPE. 



Mr. Browning has just completed the construction of an 

 entirely new spectroscope, admirably adapted to microscopic 

 investigations. Several of these instruments were exhibited 

 at the Microscopical Society, on the 11th of October, and 

 explanatory remarks were made upon them by Mr. Slack, to 

 whose microscope one had been adapted, and which he repre- 

 sented as working admirably and with great facility. 



Some time ago Mr. Sorby applied a spectroscope to the 

 microscope, using the latter instrument as a telescope, by 

 which the spectra afforded by a transparent object could be 

 viewed. Great credit was due to Mr. Sorby for thus indicating 

 a variation in the method of spectroscope inquiry, and some 

 of his results were very interesting ; but it occurred to several 

 scientific men that it would be better to apply the spectroscope 

 to the microscope than the microscope to the spectroscope, and 

 the first important step in this direction was taken by Mr. 

 Huggins, who made a communication on the subject to the 

 Microscopical Society on the 10th of May, 1865. In Mr. 

 Huggins' plan an adjustible slit was placed three or four 

 inches behind the object glass, " behind the slit at its own 

 focal distance is placed an achromatic lens/-' which transmitted 

 parallel rays to an angular- shaped spectroscope similar to the 

 ordinary kind. Mr. Huggins pointed out in the paper to 

 which we have referred, that " the spectrum of any part of a 

 microscopic object could be examined apart, and also can be 

 compared with the spectra of adjacent portions of the object. 

 In this manner the spectrum of a single blood disk, or the 

 spectrum of the contents of a single cell, can be observed, 

 and any changes in living tissues which cause a modification 

 of the spectrum can be watched and investigated." In the 



