THE RELATIONS OF THE NATURAL SCIENCES. 165 



This hourly current acts on the magnet which drops the Greenwich 

 time-hall daily at one o'clock, and on the magnet of the hourly relay 

 (to the left in Fig. 5) which completes several independent circuits, 

 each controlling a separate line of wire. One of these extends to the 

 central telegraph station at the General Post-Office in London, and 

 another to the London Bridge Station of the Southeastern Railway. 

 The hell and galvanometer marked in Fig. 5 " P. O. Telegraphs" and 

 " S. E. R. Hourly Signal and Deal Ball " show the passage of these 

 currents. 



Thus far the service is under the control of the astronomer royal, 

 and he holds himself responsible to send the signals described along 

 each line every hour of the day and night with the greatest attainable 

 accuracy. The signals are generally correct within one tenth of a 

 second of error. Should, however, by any accident, an hourly signal 

 be in error, even to half a second, another signal is immediately sent, 

 announcing that the last was not reliable. Special pains are then 

 taken that the next hourly signal be correct. Here the responsibility 

 of the astronomer royal (except for the dropping of the Deal ball, to 

 be explained later) ends. 



On the other hand, it is to be remarked that the Post-Office Depart- 

 ment, which undertakes the distribution of these signals to London 

 and the country, agrees to furnish subscribers, not with correct sig- 

 nals, but with the signals which they receive from Greenwich. The 

 Greenwich signals, however, being considered everywhere in England 

 as absolutely correct, constitute a standard from which there is no 

 appeal. 



[To be continued. ] 



-<>- 



THE RELATIONS OF THE NATURAL SCIENCES.* 



By T. STEERY HUNT, LL. D. (Cantab.), F. R. S. 



rp] 



1HE occasion which brings us together is one which should mark a 

 new departure in the intellectual history of Canada. Science and 

 letters find but few votaries in a country like this, where the best 

 energies of its thinkers are necessarily directed to devising means 

 of subduing the wilderness, opening the ways of communication, 

 improving agriculture, building up industries, and establishing upon 

 a proper basis schools in which the youth of the country may be in- 

 structed in those arts and professions which are among the first needs 

 of civilized society. The teachers, under such conditions, can do little 



* The President's Address before the Mathematical, Physical, and Chemical Section 

 of the Royal Society of Canada, at the first meeting of the society, Ottawa, May 27, 1382. 

 Reprinted, with an added note, from the " Canadian Naturalist," vol. x, No. 5. 



