550 
COLONEL SABINE ON THE INFLUENCE OF THE MOON ON THE 
well as in amount, from the conclusions which M. Kreil had derived from the Milan 
and Prague observations, as to make it plain to perceive that a knowledge of the pheno- 
mena at many different parts of the globe must be obtained, before a general theoiy 
of the nature and character of the moon’s magnetic influence could be arrived at by 
inductive reasoning. Having, therefore, in my possession a similar series of hourly 
observations at Toronto and Hobarton, which stations might with St. Helena be 
deemed to a certain extent representatives of the phenomena in the middle latitudes 
of the two hemispheres and in the tropics, I thought it best to retain the conclusions 
at St. Helena until they should be accompanied by those at Toronto and Hobarton. 
I took with me, however, to the Belfast Meeting of the British Association in Sep- 
tember 1852 an abstract of the St. Helena results, and showed them to several per- 
sons interested in magnetical researches who attended that meeting. 
The investigation has since been completed for the three stations, so fat at least as 
regards the magnetic Declination, and the results form the subject of this communi- 
cation ; to be followed, should circumstances permit, by the results of a similar 
investigation into the corresponding phenomena of the Inclination and Total Foice. 
It has appeared the most convenient arrangement to treat the stations separately, 
and to take them in the order of their succession from North to South ; commencing 
therefore with Toronto. 
Toronto. The results at this station are obtained from six years of hourly observa- 
tion, extending from July 1842 to June 1848 inclusive. The observations were re- 
ceived at Woolwich in the form of Monthly Returns, in which the scale-reading of the 
Declinometer at every hour of mean Gottingen Time was inserted in tables of double 
entry, having the hours in vertical columns and the days in horizontal lines, with the 
daily means in the last vertical column, and the monthly means at the different hours 
of solar time in the bottom horizontal line. The process at W^oolwich commenced 
by marking for omission all those disturbed observations, whensoever occurring, which 
exceeded a certain limit on either side of the monthly mean in the same month and 
at the same hour. When a disturbance was so considerable as materially to affect 
the amount of the monthly mean at the bottom of the page, a fresh monthly mean 
was taken, omitting the disturbed observation and giving fresh limiting values, by 
which the disturbances were marked afresh. The limits adopted, beyond which dis- 
turbances were omitted and within which observations were retained for the proposed 
investigation, were (at Toronto) four scale divisions (or 2'-9 in arc) above or below 
the monthly mean at the same hour. The observations retained were then marked 
in small figures on the face of the returns with the lunar hour to which each observa- 
tion most nearly corresponded. For this purpose the time of the moon’s passage of 
the meridian at Greenwich was taken from the Nautical Almanac, and corrected for 
the difference of longitude, so as to give the time of the moon’s passage of the astro- 
nomical meridian at Toronto in the mean solar time of the station. The difference 
of time corresponding to the difference between the meridians of Toronto and Got- 
