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JULY, 189S. 



The monthly meeting of the Royal 

 Society of Tasmania was held on Monday, 

 July 11, in the Art Gallery, Macquarie- 

 street. The Hon. C. H. Grant, M.E.C., 

 C,E., presided, and there was a crowded 

 attendance of ladies and gentlemen. 

 Apologies were received from the following 

 Vice-Pi'esidents : — The Hon. Sir James 

 Agnew, K.C.M.G., M.D., M.E.C., His Lord- 

 ship the Bishop of Tasmania, and Mr. 

 Thos. Stephens, M.A., F.G.ti. 



ELECTION OF MEMBERS. 



Mr. Malcolm Harrison and Mr. W. A. 

 Kermode were elected members of the 

 Society. 



PAPERS. 



" On the GENUS KRAUSSINA IN TASMANIA." 



By Messrs. W. H. T welvetrees, F. G. S. , 

 and W. F. Petterd, C.M.Z.S. 



Mr. Alexander Morton, secretary and 

 librarian of the Society, read a paper 

 entitled " On the Genus Kraussina 

 in Tasmania," by Messrs. W. H. Twelve- 

 trees, F.G.S., and W. F. Petterd, C.M.Z.S. 

 The paper dealt with an interesting group 

 of moUusca found chiefly at the mouth 

 of the River Tamar and in Long Bay at 

 low water mark. 



Ml'. R. M. Johnston spoke in praise of 

 the important work in which the writers 

 of the paper were engaged. 



" Telegraphy without wires." 

 By Thos. Self. 



Mr. Thomas Self read a paper on " Tele- 

 graphy without wires," and made some 

 interesting experiments in the presence of 

 the audience. There Avere two trans- 

 mitters — one before the lecturer and the 

 other entirely outside the room — and it 

 was shown by the continual ringing of 

 a bell in the apparatus in front of the 

 lecturer that there was continual connec- 

 tion between the two, though the con- 

 nection was invisible. When the door of 

 the room was shut the connection con- 

 tinued. Mr. R. M. Johnston left the room 

 and sent a message to Mr. Self, congratu- 

 lating the Royal Society on the success of 

 telegraphy without wires. Mr. Self pro- 

 mised that on some future occasion he 

 would repeat his experiments, when he 

 would open up communication between the 

 Museum in Argyle-street and the Govern- 

 ment Technical School in Bathurst-street. 



The following is a condensation of Mr. 

 Self's paper :— I am going to do my best 

 this evening to introduce to you one of 

 those unknown iiiysteries of the Great 

 Master. By means of an electric spark 

 we set in motion ethereal or magnetic 

 waves, called the Hertzian waves, by 

 which we are able to signal across space. 

 It is often said that we do not know what 



this unknown, silent, unseen, and powerful 

 thing called electricity is, and there is a 

 considerable amount of truth in the 

 statement. The more we learn the less 

 we know about it. It is not so 

 true, however, as it was some 20 years ago. 

 Some things are beginning to be known 

 about it ; and though modern views are 

 tentative, and may well require modifica- 

 tion, nevertheless great progress has been 

 made. I shall endeavour to explain the 

 means employed to control and use this 

 unknown thing called the Hertzian waves 

 —one of those hidden mysteries brought to 

 light by Signer Marconi. There can be 

 no doubt that Marconi is the true inventor. 

 He was the originator of the elevated 

 electrodes on the receiver and transmitter, 

 and this detail appears to have contributed 

 more to extend the possible distance of 

 telegraphy by electric waves than any- 

 thing that has been discovered since the 

 time of Hertz and Branly. The term 

 elevated electrodes in connection with 

 wireless telegraphy is not a happy one. 

 It does not convey a clear idea of the 

 apparatus used for long distances. Signor 

 Marconi attaches a vertical wire to 

 one of the terminals of his in- 

 strument at each station, by means 

 of a kite made of aluminium, or a balloon 

 which is covered with tinfoil, or it may be 

 a sheet of copper hung on a high pole to 

 which a vertical wire is attached, and 

 brought to one of the terixiinals of the 

 instrument at each station, the other be- 

 ing put to earth. The wire is surmounted 

 by a metal shape to give additional capacity, 

 and experiments seem to show that slightly 

 better results are obtained with the 

 capacity than without it. However that 

 may be, there is no doubt whatever that 

 the vertical wire is the essential feature. 

 To obtain good results the wire must be 

 vertical, as may be seen from the following 

 extracts from notes on actual experiments 

 that have been carried out. 1. Verticalwire. 

 100ft. in height, earthed at transmitter 

 and I'eceiver, distance signalled 4 miles. 



2. Same wire placed horizontally— loOyds. 



3. Vertical wire 100ft. at transmitter and 

 copper strips at receiver— 30yds. 4. Same 

 wire fixed at receiver and transmitter fitted 

 with gipherical electrodes only — 40yds. 

 5. Vertical wire 50ft. at both stations 

 gave 3 miles. 6. Same wires placed 

 horizontally about 50yds. 7. Vertical 

 wires 50ft. at both stations earthed 

 at transmitter only— 1,100yds. 8. Same 

 wires ; earth at receiver only — 2 

 miles. 9. Copper strips substituted at 

 both ends— 30yds. 10. A horizontal wire, 

 350ft. long, was erected 12ft. from the 

 ground at each station. The transmitter 

 was placed one mile from the receiver. No 

 signals were observed, even with the most 



