135 
1892-93.] Dr William Pole on Colour-Blindness. 
At the red end, trying several lines, potassium, &c., I could see 
everything that Dr and Mrs H. saw. At the violet end, I saw the 
two H lines exhibited by calcium, and also when dark, but only 
faintly. Mrs H. could see farther at this end than Dr H., and he 
could see farther than I. On the whole, my length of spectrum 
does not differ materially at either end from that of normal eyes. 
Dr Huggins showed me a copy of Fraunhofer's diagram of the 
gradations of luminosity in the spectrum. I made, at his sugges- 
tion, observations by putting a wedge of grey glass in front of the 
spectroscope, increasing the thickness till I shut out the light. 
These observations showed that the gradations of luminosity in the 
various parts of the spectrum correspond in my vision with the 
normal condition. 
LIST OF SOME WORKS AND PAPERS 
That are referred to in the foregoing Data, or have been examined 
with reference to Dr Pole’s Paper on Colour-Blindness. 
ABBREVIATIONS. 
“ ORiEFE.” — Yon Grsefe’s Archiv fur OpJithalmologie, Berlin. 
“Du Bois-Reymond.”— filr Anatomie unci Physiologic (Physiologi- 
cal Part). Leipzig. 
“ Pfluger.” — Archiv fur Physiologic, Bonn. 
Aitken, John. 
“ On Colour and Colour Sensation,” Proc. Pioyal Scottish Soc. Arts, 1871-2. 
Aubert, Herrmann. 
“Ueber die Grenzen der Farbenwahrnehmung auf den seitlichen Theilen 
des Retina.” Grsefe, vol. iii. part 2, 1857. 
Becker, Otto. 
“ Ein Fall von angeborner, einseitiger totaler Farbenblindheit.” Grsefe, 
vol. XXV. part 2, 1879. 
Benedict, Moritz. 
“ Der Daltonismus bei Sehnervenatrophie.” Grsefe, vol. x. part 2, 1864. 
Benson, AY. 
“ Manual of the Science of Colour.” London, 1871. 
Berry, G. A., Edinburgh. 
“Remarks on the Examination and Classification of Cases of Colour-Blind- 
ness.” Edinburgh, 1879. 
