The Abyssinian Expedition. 227 



greens sometimes seen on the Moon, and which are very rarely 

 distinct to me. 



I should not have thought so much of the discrepancy 

 between what we saw and what Mr. Browning saw about five 

 hundred yards N.E. of us, if we had not ascertained by com- 

 parisons that our perceptions of colour and his are pretty much 

 alike. Can it be that the difference arose chiefly from his 

 employing a much larger aperture ? And does the eye become 

 insensible to' small quantities of red, when accompanied by a 

 good deal of white light ? Presuming the Moon during eclipse 

 to omit red and white, or whitish-yellow, light, the larger 

 aperture would collect more of both, but it does not follow 

 that both would look more intense to the eye • the red might 

 be overpowered as the white light increased, although its 

 proportion to the white light might be the same. My opera- 

 glass, which is unusually free from chromatic errors, made the 

 Moon look much redder than the telescope, and Mr. Barnes's 

 instrument being much larger than mine might have still 

 further diminished the red aspect. 



In the presence of Mr. Browning I made several experi- 

 ments with red objects under the microscope, such as trans- 

 parent pieces of dark orange-red glass, a red leaf of a fuchsia, 

 and a red postage-stamp. The glass, as a transparent object, 

 changes hue considerably as the amount of white (or yellow 

 white) lamp light thrown through it is varied. The postage- 

 stamp goes through similar changes as an opaque object, being- 

 very brilliant, and something* between blood-colour and ma- 

 genta, in full oblique illumination, and turning deeper and with 

 a different hue as the amount of incident light is decreased. 



To return to the Moon, we noticed, as Mr. Browning did, 

 the remarkable distinctness and light tone of the margin of 

 the eclipsed portion. 



THE ABYSSINIAN EXPEDITION. 



BY PBOFESSOE D. T. ANSTEI). 



The expedition now leaving the shores of England, and 

 the armed forces preparing to penetrate Eastern Africa from 

 the side of India under the British flag, having for their pri- 

 mary object the rescue of a few Europeans (only three of them 

 Englishmen) from the clutches of an African tyrant, cannot 

 but add something to our knowledge of a district hitherto 

 only visited by isolated travellers at long intervals. As the 

 army is to be accompanied by a scientific staff to report on the 



