APPENDIX G CV 
the Observatory to become better acquainted with the work being carried 
on by other members of the staff, and also as giving those who were 
engaged in any original investigation a convenient means of presenting 
and publishing such work. It was decided to present the technical 
papers in the afternoons, thus obtaining a full attendance of the Observ- 
atory staff, and to present an abstract of such papers at the preceding 
evening meetings, thus giving all members an opportunity of becoming 
acquainted with the character of the paper and of attending in case 
they were interested. This arrangement has worked very successfuliy, 
and the attendance and interest at all meetings has been very good. 
The papers presented at the evening meetings have each dealt fully, 
and at the same time simply, with the subjects under consideration, and 
have been well illustrated whenever possible, thus rendering them of 
much value to students of the science of astronomy. At the time of 
writing, the programme of evening papers has been completed, and the 
large attendance at each of the meetings and the interest shown are 
sufficient evidence of their value. 
The papers presented at the afternoon meetings have been of such 
a character and of such value, not only locally but to astronomical sci- 
ence in general, that each deserves a short summary of its chief points. 
The first by Mr. J. S. Plaskett, B.A., described numerous experi- 
ments and measurements showing that the star image, given by the sys- 
tem of visual objective with auxiliary photographic corrector for 
stellar spectroscopic work, was about twice as large as it should be. Thea 
cause of the aberrations, with suggestions for their remedy, was treated 
by Mr. Plaskett, while a comparison between the performance of the 
Ottawa and other equipments showed that a similar defect probably 
existed elsewhere. The construction of suitable correcting lenses, ren- 
dered possible by this investigation, will mean a marked advance in the 
range of stellar spectrographs. 
Mr. Plaskett’s paper has been published in the Astrophysical Jour- 
nal, April, 1907, and is to be published in the Journal of the Royal 
Astronomical Society of Canada. 
The second paper, by Mr. R. M. Stewart, M.A., presented in a 
clear and concise manner the results of an extended research, and one 
which has long been needed, into the cause of the discrepancies in time 
observations by the transit key. These had previously been ascribed to 
variation in personal equation, but a comparison of key and travelling 
wire micrometer methods, in the latter, personal equation being elim- 
inated, showed that the above hypothesis was not true, and Mr. Stewart 
traced the cause of the errors to defective determination of instrumental 
constants due to errors in the observations of polar stars. He is at 
