APPENDIX. 341 



decomposition of the albuminous fluid takes place. The coloured 

 albuminous solution was dichroic. It appeared red by reflected, and 

 blue by transmitted light. 



This coloured albuminous fluid is the only blue fluid known to 

 Mr. Sorby which gives particular bands. Mr. Browning describes 

 the spectrum as follows : " Commencing at the least refrangible or 

 red end of the spectrum, we find it cuts pretty sharply a short piece 

 of the extreme red. Then we have a strong absorption band also 

 in the red, corresponding to 2 \ of the twelve lines given by Sorby's 

 standard interference spectrum (pi. L, fig. 323). A second absorption 

 band in the green commences at line 4, and tones off gradually into 

 the spectrum just beyond line 5." 



The spectrum of the fluid viewed by reflected light was found 

 by Mr. Browning to be very different from the one by transmitted 

 light just described. " A much larger portion of the red end is 

 absorbed, but not so sharply. The strong band in the red is shifted 

 towards the more refrangible end of the spectrum, cutting out the 

 edge of the red, some of the orange, and most of the yellow. The 

 second absorption band is wanting, but the greater part of the light 

 of the spectrum is absorbed from a point between the fourth and 

 fifth lines, and all the light is absorbed at the yth. The part of the 

 spectrum which should be yellow, has a strong tinge of olive 

 green." 



327 a. Dr. Woodward's Improved Arrangements for taking 

 Photographs of Microscropic Objects. The description of a more 

 perfect and convenient plan than the one originally adopted by 

 Dr, Woodward, at the Laboratory of the Army Medical Museum, 

 Washington, U.S., has lately been forwarded by him to Dr. Maddox. 

 I am glad to be able to introduce the communication here, for it is 

 in itself of considerable interest, and shows, moreover, the high 

 estimation in which this branch of microscopy is held by the Govern- 

 ment authorities. See also p. 329. 



" For the sake of convenience a camera box and table are dis- 

 pensed with, and the operating room, having a window facing to the 

 south, is itself converted into a camera by wooden shutters on 

 the inside of the window, sufficient non-actinic light to enable the 

 operator to move about freely being admitted through yellow panes 

 in a sashed door. A small yellow pane is also let into one of the 

 window shutters to enable the operator to watch the sky during an 

 exposure and see when clouds are about to obscure the sun. The 

 microscope with its body in a horizontal position, stands on a shelf, 

 on the inner window sill, its feet fitting into brass sleets to insure 

 accuracy of position, pi. LXIX, fig. 417. Covering the portion of 



