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72 “A subsequent computation showed that this phenomenon took place over the southern part of Schiaparelli’s Protei Regio. Other reasons lead me to think, however, that he has placed that island some 5° too far south.

“On November 26 the cloud promptly appeared at 17h. 15m., G. M. T., but about 12° farther north. Instead of remaining continuously visible, it dissipated and reformed at irregular intervals. The first appearance lasted sixteen minutes. After somewhat over four minutes had passed, it reappeared momentarily, and six minutes elapsed before it appeared again, lasting then but two and one half minutes. Then followed an absence of three minutes, presence for two minutes, absence for three minutes, presence for one minute, and a final brief appearance eight minutes later at 18h. 1m. Its presence was suspected five minutes before that hour, and again at 18h. 11m., but with great uncertainty.

“At this time it presented in general the same characteristics as the night before, though its appearances were too brief to permit such careful observations as were hoped for. The seeing, too, was not so good as before, varying from 4 to 7; and if the cloud happened to appear under the former figure, its observation was difficult. It is needless to remark that under such conditions it was impossible to