LVIII THE ROYAL SOCIETY OF CANADA 
by different observers have appeared, some of which are of greater 
magnitude than the above difference. The law of decrease of the 
velocity of rotation with increase of solar latitude is of practically the 
same form as determined previously. Possibly the most important 
result obtained has been to show, by the discussion of very large num- 
bers of residuals, that, so far as these measures are concerned, there are 
no systematic differences in the velocity obtained from lines of different 
elements. It is proposed to continue this work during the coming 
summer. 
The two azimuth marks are now in use in transit circle work. 
Permanent houses to protect the piers and marks are to be erected 
shortly. An examination of the changes of azimuth and of level during 
the last two years has shown these to be very small and the stability 
of the pier and transit to be very satisfactory. The mounting of the 
circle microscopes is not sufficiently rigid, so that a change to the form 
of mounting used on the Repsold circles is contemplated. 
Observations of right ascension have been carried on continuously 
so far as possible since March, 1910; in that year 5,371 and in 1911, 2522 
transits were observed. This year there are a sufficient number of 
observers to admit of observing from evening until morning. The 
reduction of the 1910 observations is about completed and the deduced 
right ascensions ready for publication. There were 2,428 zenith dis- 
tances observed last year, including many stars whose declinations are 
required for our latitude determinations. 
A rigid investigation of pivot errors has been made this year and 
the results computed and tabulated. 
The chief advance in the Observatory Time Service has been the 
installation of the Magneta clock system in the Victoria Museum, 
which is much superior to that employing batteries. As the Master- 
clock is self-winding and there are no batteries or contact points very 
little attention is required. 
During the past calendar year the two Bosch photographie pendu- 
lums have recorded seventy-five earthquakes in various parts of the 
world, and 18 bulletins have been issued to 61 stations. 
From the Observatory have been issued stereographic projection 
tables computed for the more important stations of the world for 
facilitating the location of earthquake epicentres, and the method 
based thereon has found very general use and acceptance. 
Dr. Klotz represented Canada at the International Seismological 
Conference in Manchester, England, last July. Besides presenting 
several papers he succeeded in having adopted a uniform nomenclature 
and form of bulletin for earthquakes, which was badly lacking hereto- 
fore. 
