1905.] on Recent Advances in Wireless Telegraphy. 43 



which ships, throughout their voyage across the Atlantic, receive 

 daily news messages collected for transmission by Messrs. Renter in 

 England, and by the Associated Press in America. At present five 

 transatlantic steamships are thus publishing a daily newspaper con- 

 taining telegraphic messages of the latest news. 



The practical and experimental work carried out in connection 

 with the long- and short-distance stations has afforded valuable 

 opportunities "for noting and studying various unknown and un- 

 expected effects of the condition of space on the propagation of 

 electro-magnetic waves. 



The author being able to avail himself of the daily reports of 

 over 70 ships and 50 land stations, the chances of eiTor from what 

 might be termed accidental results are reduced to a minimum. Thus 

 it is interesting to observe that the difference between the propaga- 

 tion of the wave by day and by night is only noticeable in the case 

 of long-distance stations ; or, in other words, where a considerable 

 amount of energy is forced into the transmitting aerial wires. For 

 instance, all the" short-distance ship-to-shore stations having a range 

 of about 150 miles, averaged the same distance of communication by 

 day as by night ; but the long-distance stations, such as Poldhu, 

 Cape Breton and Cape Cod, as" originally constnicted, averaged by 

 day two-fifths of the distance covered by night. 



The opinion has been expressed that the reason for shorter dis- 

 tances being covered by day is due to the electrons propagated into 

 space by the sun, and that if these are continually falhng like a 

 •shower upon the earth, in accordance with the hypothesis of Professor 

 AiThenius, then that portion of the earth's atmosphere which is facing 

 the sun will have in it more electrons than the part which is not facing 

 the sun, and therefore it may be less transparent to long Hertzian 

 waves. 



The full scientific explanation of this fact has not yet been given, 

 but Professor J. J. Thomson has shown in an interesting paper in 

 the PhUoso])hical Magazine* that if electrons are distributed in a space 

 traversed by long electric waves, these will tend to move the electrons 

 in the direction of the wave, and will therefore absorb some of the 

 •energy of the wave. Hence, as Professor Fleming has pointed out in 

 his Cantor Lectures dehvered at the Society of Arts, a medium through 

 which electrons or ions are distributed acts as a shghtly turbid medium 

 to long electric waves. 



In fact, clear sunlight or blue skies, though very transparent to 

 light- waves, may act as a fog to Hertzian waves. Apparently the 

 amplitude of the electrical oscillations radiated has much to do with 

 the interesting phenomenon, for the author has found that if a con- 

 siderable amount of power is applied to the radiating apparatus of 

 the so-called short distance stations, the difference between the range 



♦ Vol. iv. Series 6, August 1902. 



