270  H. Draper—Oxygen in the Sun. 
After the reading of the paper, Dr. Draper showed some 
exquisitely sharp negatives of the solar and oxygen spectra, 
which he had obtained, and handed round some paper enlarge- 
ments, some two feet long, for inspection by the meeting. 
Mr. Raayard: After the reception that has been given to Dr. 
Draper, I do not think I need say anything about the impor- 
tance of the research he has undertaken. When a couple of 
years ago he sent over copies from his former photographs on a 
much smaller scale, I then ventured to say that I thought the 
probability of the proposition which he laid down was very 
great indeed, amounting to some thousands to one, and I should 
like now to point out how enormously the probability has been 
increased by these more recent experiments. If Dr. Draper has 
increased his dispersion four times he has not merely increased 
the probability of his case four times, but he has increased the 
value of every coincidence he shows four times. On looking 
at the original photographs (which show the coincidences more 
sharply than the paper prints) I counted eighteen oxygen lines, 
and, therefore, the increase of probability on the present occa- 
sion, as compared with the former occasion, is as four to the 
power of eighteen to one, a very enormous number. There 
in the solar spectrum. Ifa line were thrown at random best 
bright part of the solar spectrum would be as the total breadth 
of the bright part of the solar spectrum to the total breadth of 
gen line being on one side and coinciding with one edge of the 
Bee oR ; but this is accounted for by the fact that there are 
ably other bright lines in the solar spectrum besides oXY- 
