ApEir 26, 1907] 



'SCIENCE 



667 



'The Occurrence of Elemental Silicon in a Me- 

 teoric Iron.' 



THE PHILOSOPHICAL SOCIETY OF WASHINGTON 



A SPECIAL meeting of the society was held 

 on March 21, 1907, at the JJ. S. Bureau of 

 Standards, for the purpose of hearing a paper 

 on ' The Determination of the Temperature 

 of the Sun, and Recent Solar Theories,' read, 

 hy special request of the society, by Professor 

 Dr. Otto Lummer, of the University of Bres- 

 lau. An informal reception followed upon the 

 close of Dr. Lununer's discourse. 



The 632d regular meeting of the society was 

 held on March 30, 1907, President Hayford in 

 the chair. The first paper of the meeting was 

 presented by Mr. Elliott Woods (read by Mr. 

 Mark A. Woodell at the author's request) 

 upon ' Recreations in Wireless,' the writer in- 

 troducing his theme with a brief mention of 

 his early laboratory experiments in electricity 

 and a statement of how his attention and in- 

 terest were first drawn to wireless telegraphy. 

 Some of the characteristics of wireless teleg- 

 raphy were then described. Wireless teleg- 

 raphy speaks by means of vibrations im- 

 pressed upon that assumed substance, the 

 ether, in which case two capacities are elec- 

 trically charged to a point where the resistance 

 of the air breaks down and a spark passes 

 between the terminals of the capacities when 

 these are suitably disposed according to the 

 potential of the E.M.F. employed. This 

 spark is the seat of the impressing energy on 

 the ether. The waves thus produced proceed 

 in a circular surface formation. The next 

 step is the receipt of these energy waves. It 

 requires that there be some mechanical device 

 which will absorb the incoming energy of the 

 waves and which in its details must vibrate in 

 unison with these incoming oscillations or 

 waves. It was then stated that messages are 

 received in two ways, either by automatic 

 registration on a tape or by ear, receiving the 

 signals by means of the so-called electrolytic 

 receivers. 



Two things appear essential for wireless 

 communication, i. e., harmony in wave vibra- 

 tion between source of power with which we 

 impress the energy and the wave period of 



vibration of the medium upon which our 

 power is impressed to form the waves, i. e., 

 the closed sending circuit and the aerial. 

 These desirable conditions are found by meas- 

 urements with a specially designed apparatus 

 known as electric wave meters. A brief de- 

 scription was given of the different parts of a 

 wireless equipment, and the uses of the elec- 

 tric wave meter in measuring the vibratory 

 wave-lengths of the two branches of the system 

 to accomplish harmony of relation. In de- 

 scribing the process of receiving the waves it 

 was stated that as aerials vary in length in 

 nearly every ease, so their periods of vibra- 

 tion vary, hence ' tuning ' must be resorted to 

 if stations at any distance are to be heard. 

 In the course of the author's remarks concern- 

 ing some of his experiences in the operation 

 of a wireless station it was stated that day- 

 light signals as received were weaker than 

 night signals, and he was inclined to attribute 

 this to the fact of fewer signals being sent 

 at night. Experience also showed that signals 

 could be heard better on cloudy nights than 

 on clear ones. Instances were cited which 

 seemed to indicate that intervening land areas 

 have an effect upon the receiving of messages. 

 Static wave disturbances were discussed as to 

 their general effect, as revealed by the author's 

 experience. One of the conclusions reached 

 by the author in studying the relations of 

 atmospheric conditions to ' wireless condi- 

 tions ' was that there was no doubt in his 

 mind as to the ability of the wireless receiver, 

 aided by the static conditions which it regis- 

 ters, to show even ahead of the barometer the 

 oncoming of a serious change in the weather, 

 even when the sky doesn't indicate such a 

 change. It was the writer's opinion that the 

 greatest field of labor lies in studying the 

 relations of atmospheric conditions to form 

 of waves sent out under present method of 

 wireless transmission. In the concluding re- 

 marks of the paper the commercial benefits of 

 wireless telegraphy were briefly noted. 



The last paper of the evening was presented 

 by Mr. Asaph Hall, Jr., under title of 'Dis- 

 cussion of some Errors of Meridian Circles.' 

 The introductory remarks included a descrip- 

 tion of some meridian circles. The principal 



