Sept. 19, 1884.] 



KNOWLEDGE 



239 



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CANDROMEDA] 



[PISCES] 



«42. <■' 



;'«45 



-. *"*30. 



tCETUSD 



Night Sign for the Month. 



ZODIACAL MAPS. 



By Richard A. Proctor. 



^"¥TE give this week both the day sign and the night sign 

 V \ for the month, one showing the zodiacal sign now 

 high in the heavens at midnight, the other showing the 

 region of the zodiac athwart which the sun pursues his 

 course at this part of the year. 



THE BRITISH ASSOCIATION OF 

 SCIENCE. 



LORD RAYLEIGH'S opening address occupied nearly 

 an hour and a half in its delivery. In liis opening 

 remarks he mentioned that for more than fifty years the 

 Association held its gatherings in various towns in the 

 United Kingdom, there being few places of any importance 

 which were not visited. Not being satisfied, they sought 

 to conquer new worlds, hence the present meeting in 

 Montreal. When first proposed the project was looked 

 upon with disfavour, as once the thin edge of the wedge 

 was admitted there was no telling to what it might lead. 

 The British Empire being so rapid in its development, there 

 was a prospect of such out-of-tlieway places as London and 

 Manchester no longer being able to claim a visit of the 

 Association except as a concession to the susceptibilities of 

 the English. Whatever objections were at first felt were 

 soon overcome by the prospect of the magnificent oppor- 



tunity of members of the Association becoming ht-XU r 

 acquainted with the Queen's dominion in this part of the 

 world. He then referred to the loss sustained to science 

 by the death of W. Siemens. The speaker then reviewed 

 the striking advances made of late years in the production 

 and application of electricity upon a large scale, and also 

 touched upon the inventions of the telephone and phonu- 

 graph. 



THEORETICAL ACOUSTICS. 



In referring to theoretical acoustics he said : Pro- 

 gress has been steadily maintained, and many phenomena 

 which were obscure twenty or thirty years ago have since 

 received adequate explanation. If some important practical 

 questions remained unsolved one reason is they have not 

 been definitely stated. Everything in connection with the 

 ordinary use of our senses presents peculiar difiiculties to 

 scientific investigation — some kinds of information with 

 regard to their surroundings are of such importance to 

 successive generations of living beings that they have 

 learned to interpret indications which, from a physical 

 point of view, are of the slenderest; we are in the habit of 

 recognising without much difficulty the quarter from which 

 a sound proceeds, but by what means we attain that end 

 has not yet been satisfactorily explained. It has betn 

 proved that when proper precautions are taken we are 

 unable to distinguish whether a pure tone as from a vibrat- 

 ing tuning fork held over a suitable resonator comes to us 

 from in front or from behind. This is what might have 

 been expected from an r> priori jioint of view, but what 

 would not have been expected is that with almost any other 



