264 



NA TURE 



[April 29, 1909 



Department of Agriculture include a Bulletin on the peach- 

 tree bark-beetle {Phlacotribiis liminaris), by Mr. H. F. 

 Wilson, a paper on the orange-thrips iEuihrips citri), 

 named for the first time, by Mr. D. Moulton, and a leaflet 

 on fleas. 



Starting with the fact that no sensible difference between 

 the variability of the sexes in the human species can be 

 found, if accurate measures be taken to determine that 

 variability, it is of considerable interest to ascertain 

 whether there is differentiated variability in the castes of 

 the social insects. In a memoir published in Biomdtrika, 

 vol. v., it was shown that the worker-wasp was more 

 variable than the drone, and the drone than the queen. 

 In vol. vi., part iv., of the same serial, Dr. Ernest 

 Warren investigates the variability of the six castes of 

 South .African white-ants, or termites. The author finds 

 that the sexual are less variable than the asexual castes, 

 and considers that the difference of variability between the 

 inhabitants of different nests cannot be accounted for by 

 heredity, but must be due to post-embryonic environmental 

 influences. It is also held that the relative variability of 

 the whole population as compared with that of a single 

 nest cannot be attributed to heredity, but must be due to 

 the influence of environment on a plastic organism. Dr. 

 Warren finds a high correlation between the mean sizes of 

 the different castes in the same nest, and little correlation 

 between the variability of different castes in the same nest, 

 thus indicating that a similar environment does not affect 

 the different castes in the same way. 



In the .'\pril number of the Zoologist Mr. A. H. Swinton 

 continues his account of the vocal and instrumental music 

 of insects. 



TRANSATLANTIC WIRELESS TELEGRAPHY.' 



II. 

 T N the spring of 1903 the transmission of news messages 

 -•■ from America to the London Times was attempted, in 

 order to demonstrate that messages could be sent from 

 America by means of the new method, and for a time these 

 messages were correctly received and published in that 

 newspaper. 



By reference to the files of the Times I find that 267 

 words of news, transmitted across the Atlantic by wireless, 

 were published in the London Times during the latter part 

 of March and the early part of April of that year. A 

 breakdown in the insulation of the apparatus at Glace Bay 

 made it necessary, however, to suspend the service, and, 

 unfortunately, further accidents made the transmission of 

 messages uncertain and untrustworthy. In consequence of 

 this it was decided not to attempt, for the time being, the 

 transmission of any more public messages until such time 

 as a trustworthy service could be maintained in both direc- 

 tions under all ordinary conditions. 



As I found that many improvements evolved during the 

 course of the numerous tests and experiments could not 

 be readily applied to the plants at Poldhu and Cape Breton, 

 it was decided to erect a completely new long-distance 

 station in Ireland, and to transport the one at Glace Bay 

 to a different site in the vicinity, where sufficient land was 

 available for experimenting with aerials of much larger 

 dimensions than had been hitherto employed. 



Experiments were, however, continued with Poldhu, and 

 in October, 1903, it became possible to supply the Cunard 

 steamship Lucania, during her entire crossing from New 

 York to Liverpool, with news transmitted direct from the 

 shore. 



In November of the same year tests similar to those 

 carried out with the Italian cruiser took place on behalf 

 of the British Admiralty between Poldhu and H.M.S. 

 Duncan, 



Communication with Poldhu was maintained during the 

 entire cruise of this battleship from Portsmouth to 

 Gibraltar, and further communication was established 

 between Poldhu and the Admiralty station situated on the 

 Rock of Gibraltar. It should be' noted that the distance 

 between Cornwall and Gibraltar is 1000 miles — 500 over land 

 and 500 over water. 



„, „ - 5 delivered at the Riyal Institution on Friday, March 13, 



1908, by Commendatore G. Marcini. Continued from p. 337. 



The aerial at Poldhu was shortly afterwards extended by 

 the addition of wires sloping downwards, umbrella-fashion, 

 as shown in Fig. 10. This increased the capacity of the 

 aerial, and some further tests were carried out with a 

 station at Fraserburgli, in the north of Scotland. From 

 these tests considerable advantage appeared to be derived, 

 at least for communication over land, by the adoption of 

 much longer waves than had been hitherto employed, and 

 with a wave-length of 14,000 feet it was found possible to 

 telegraph over a distance of 550 miles with an expenditure 

 of energy of about i kilowatt. 



The operation of the long-distance stations in England 

 and America made it possible to transmit messages to ships, 

 whatever their position, between Europe and North 



America ; and to the Cunard Company belongs the credit 

 of having greatly encouraged the long-distance tests, a 

 circumstance which enabled them to commence, in June, 

 1904, the regular publication on their principal vessels of a 

 daily newspaper, containing telegraphic messages of the 

 latest news from Europe and America. 



This daily newspaper has now been adopted by nearly 

 all the large liners plying to New York and the Mediter- 

 ranean, and it obviously owes its entire existence to long- 

 distance wireless telegraphy. Therefore the tranquility and 

 isolation from the outside world, which it is still possible 

 to enjoy on board of some ships, is rapidly becoming a 

 thing of the past ; but, however much travellers may sigh 

 over the innovations which have lately been brought about, 



ihcy seem anxious enough to avail themselves of the new 

 method of communication on all possible occasions. 



Early in 1905 the construction of the new station at 

 Glace Bay was sufficiently advanced to allow of preliminary 

 tests being carried out. The aerial was very large, and 

 consisted of a vertical portion in the middle 220 feet long 

 supported by four towers and attached to horizontal wires, 

 200 in number, each 1000 feet long, extending radially all 

 round, and supported at a height of 180 feet from the 

 ground by an inner circle of eight and an outer circle of 

 sixteen masts (Fig. 11). The natural period of oscillation 

 of this aerial gave a wave-length of 12,000 feet. The 

 capacity employed was i-8 microfarads, and the spark-length 

 J-inch. 



Signals and messages from this station were received at 



NO. 2061, VOL. 80] 



