112 



science: 



[N. S. Vol. XV. No. 368. 



of the conditions seems to lead to another con- 

 clusion. The recent epidemic of tetanus in 

 Camden, N. J., prompted the local Board of 

 Health to send out a circular giving the facts 

 collected by the Board. From this circular it 

 appears that a bacteriological examination of 

 the vaccine matter used in Camden showed 

 it to be free from tetanus germs. The reason 

 for the epidemic is found in the prevailing 

 weather conditions, combined with careless- 

 ness on the part of persons recently vacci- 

 nated. There had been a long spell of dry 

 weather, accompanied by high winds, which 

 raised the dust, so that there were tetanus 

 germs constantly present in the atmosphere. 

 Infection resulted when the scabs had been 

 removed, and the germs gained access to the 

 wound. 



E. DeC. Ward. 



WIRELESS TELEaRAPHY. 

 The readers of Science may be interested 

 in the following editorial taken from the Lon- 

 don Electrician of December 20. It seems to 

 us also that the Marconi system cannot be ex- 

 pected to replace submarine cables, which 

 form at present a network which appears al- 

 most as complicated on a small map of the 

 world as the network of railways on an ordi- 

 nary map of the State of Illinois. An attempt 

 to substitute the Marconi system for existing 

 cables would lead to a state of affairs 

 closely analogous to the confused din in a 

 stock exchange where each person makes more 

 noise than all the rest. This analogy enables 

 one to appreciate the limitations of wireless 

 telegraphy. In the one case we have electrical 

 waves and in the other ease sound waves 

 spreading in all directions from each sending 

 station; and we must remember that Mar- 

 coni's receiver is far inferior to the hirman 

 ear in its ability to analyze a complicated 

 system of waves falling upon it, or, in other 

 words, to respond selectively to certain types of 

 waves. 



W. S. Franklin. 



" The current week opened with the startling 

 arniouncement throvighout the world that Mr. 

 Marconi had succeeded in transmitting wireless 

 signals across the Atlantic. By means of a 



kite he had contrived, at St. John's, Newfound- 

 land, to intercept waves transmitted from Corn- 

 wall, the actual receiver being a telephone and the 

 actual ' message ' the Morse letter ' S ' at in- 

 tervals of five minutes, as prearranged. The 

 sounds were very faint, though they are declared 

 by Mr. Marconi himself to have been unmistak- 

 able. Thursday, December 12, 1901, may prove, 

 therefore, to be a date to be remembered in the 

 history of wireless telegraphy. Within this ap- 

 parently feeble result — three very faint clicks 

 repeated at intervals of five minutes — there is 

 to be seen the germ of ocean wireless telegraphy, 

 and, perhaps, telephony. It is a germ that 

 promises to develop into abundantly fruitful ma- 

 turity. It is not in the interlinking of continents 

 divided by an ocean, but rather in the overspread- 

 ing of the ocean itself with telegraphic facilities 

 that the power and fruitfulness of this latest 

 achievement of Mr. Marconi is to be perceived. 

 Submai-ine cables already link ocean-divided con- 

 tinents far better than wireless telegraphy can 

 ever do. Long ago we pointed out that the true 

 field of wireless telegraphy is across compara- 

 tively short distances of water — that, in fact, 

 it is really a disadvantage to ivireless telegraphy 

 to be able to take in such a wide compass as an 

 entire ocean. Indeed, when such immense areas 

 are covered the probabilities of confusion and 

 clashing of signals is a thousandfold increased. 



Lest any section of the public should be dis- 

 posed to regard Mr. Marconi's latest experiment 

 as foreshadowing the replacement of submarine 

 telegraph cables by wireless apparatus, we hasten 

 to bid them dismiss the idea. No serious competi- 

 tion with submarine telegraphy can ever take 

 place on a commercial basis, at any rate until 

 the Marconi system is evolved into something 

 very difi'erent from what it now is. This raises 

 the interesting but thorny question of patent 

 rights. Others besides Mr. Marconi will have 

 something to say on this head. We do not say 

 that Mr. Marconi will not succeed in sending 

 messages between this country and America ; 

 but, having regard to the uncommercial condi- 

 tions under which they must be sent, it is clear 

 that the wireless channel of transmission will be 

 rigorously avoided by business men, to whom a 

 guarantee of secrecy and the certainty of a re- 

 corded message are absolutely indispensable. 

 Wireless signals in the ether can never be secret; 

 it must always be possible to intercept them. 

 And messages received in no more permanent 

 form than by sounds in a telephone are too 

 evanescent and uncertain to commend themselves 



