1916 - 17 .] 
Meetings of the Society 
397 
TWELFTH ORDINARY MEETING. 
Monday , June 4, 1917. 
Dr John Horne, Esq., LL.D., F.R.S., F.G.S., President, in the Chair. 
The Makdougall-Brisbane Prize award for the Biennial Period 1914-1916. 
The Council of the Royal Society of Edinburgh having awarded the Makdougall-Brisbane Prize 
to Robert Alexander Houstoun, Ph.D., D.Sc., for his series of papers on “ The Absorption of 
Light by Inorganic Salts,” published in the Proceedings of the Society ; and the Gunning Victoria 
Prize award for the Quadrennial Period 1912-1916, to Sir Thomas Muir, C.M.G., LL.D., F.R.S., 
for his series of memoirs upon “The Theory and History of Determinants and Allied Forms,” 
published in the Transactions and Proceedings of the Society between the years 1872 and 1915 ; 
these Prizes will be presented at the July Meeting. 
The following Communications were read : — 
1. The Highland Border Rocks in the Aberfoyle District. By Professor T. J. Jehu and Dr 
Robert Campbell. ( With Lantern Illustrations. ) 
2. On Knots, with a Census of the Amphicheirals with twelve Crossings. By Miss Mary G» 
Haseman. Communicated by the General Secretary. 
THIRTEENTH ORDINARY MEETING. 
Monday , June 18, 1917. 
Dr John Horne, Esq., LL.D., F.R.S., F.G.S., President, in the Chair. 
The Makdougall-Brisbane Prize award for the Biennial Period 1914-1916. 
The Council of the Royal Society of Edinburgh having awarded the Makdougall-Brisbane Prize 
to Robert Alexander Houstoun, Ph.D., D.Sc., for his series of papers on “The Absorption of 
Light by Inorganic Salts,” published in the Proceedings of the Society ; and the Gunning Victoria 
Prize award for the Quadrennial Period 1912-1916, to Sir Thomas Muir, C.M.G., LL.D., F.R.S. , 
for his series of memoirs upon “The Theory and History of Determinants and Allied Forms,” 
published in the Transactions and Proceedings of the Society between the years 1872 and 1915 ; 
these Prizes will be presented at the July Meeting. 
The following Communications were read : — 
1. On the Improvement of the Gregorian Calendar. The Discussion was opened by Alexander 
Philip, LL.B. ( With Lantern Illustrations .) 
Mr Philip stated that his object was to simplify the calendar so as to maintain the date of the 
vernal equinox at or about the 21st of March, since any alteration involving a change in that date 
involved also a change in the tables for the calculation of Easter. He believed that many of the 
advantages of a real simplification could be obtained by taking one day from August and adding it 
to February of the following year. This proposal was superior to any other which had been formu- 
lated, and might easily receive the cordial support of the most conservative defenders of the 
Gregorian calendar. Moreover, the change could be effected without any trouble, disturbance, or 
expense. If such a change were carried out, further advantages could be obtained by making the 
almanac year run from the 1st of March. In this case only one Dominical letter would be required 
for each year, whether leap year or common year. By this change also the year would be divided 
into four three-monthly quarters of 91 days, and on the basis of such a calendar Mr Philip 
showed that a Perpetual Calendar could be subsequently established with a minimum of 
disturbance. 
Dr W. B. Blaikie and Professor Sampson took part in the discussion and expressed the opinion 
that if any change was to be made they preferred Mr Philip’s earlier suggestion, as described to 
the Society some years ago (see his Proposal for a Simplified Calendar (1907), and The Reform of 
the Calendar (1914)). 
2. Note upon an Observation on Insects and Light. By Professor J. Graham Kerr, F.R.S. 
