July i i, 1907] 



NA TURE 



259 



Observatory, and gives the designations, positions, magni- 

 tudes, magnitude ranges, and spectral classification of 

 fifteen new variable stars discovered in the regions covered 

 by the Harvard maps Nos. 31 and O2. 



Names for the Tiikee Jovian Asteroids. — Drs. Wolf 

 and Kopff have chosen the three names Achilles, Hector, 

 and Patroclus, respectively, to designate the three important 

 minor planets {5S8) [igofa TCi], [1907 XM], and [1906 VY] 

 discovered by them at Heidelberg. Readers of these 

 columns will remember that the orbits of these three bodies 

 have been found to extend as far from the sun as that of 

 Jupiter {AsiYO)\omisc\n: Nticlnichten, No. 4187, p. 192, 

 June 29). 



The Mira Maximum of 1906-7. — From a series of 

 observations made at Utrecht, and extending from July 25, 

 1906, to March 4, 1907, Prof. Nijland found that the 

 ma.ximum brightness of Mira occurred on December 7, 

 when the magnitude was 2-0. The preceding minimum 

 was recorded on August 7, and, as seen from the curve, 

 was a very flat one, from which a sharp rise to an 

 exceptionally bright ma.ximum tooii place. The previous 

 maximum took place on January 3, igoti, so that the 

 period between these two successive maxima was 338 days 

 (AstronomiscJic Nachrichtcn, p. 113, No. 4183, June 14). 



SoL\R Prominence Observations in 190b. — The annual 

 summary of the results of the prominence observations 

 made at Catania, for 1906, is published by Prof. Ricc6 

 in No. 5, vol. xxxvi. (p. 73), of the Mcmorie deUa Societd 

 degli Spettroscopistt Italiaiii. The daily record is repro- 

 duced, and then analysed, under the heads of the ex- 

 tension, height and frequencies of the prominences, in the 

 two hemispheres for each month and quarter and for the 

 year. The similarity of the size and distribution of the 

 prominences recorded to those of the previous year 

 indicates a stationary point characteristic of the maximum, 

 whilst the greater frequencv during March points to that 

 month as being the actual month of solar prominence 

 maximum. 



CONGRESS OF THE ROYAL INSTITUTE OF 



PUBLIC HEALTH. 

 HTHE congress of the Royal Institute of Public Health, 

 ^ held this year at Douglas, Isle of Man, from June 29 

 to July S, was presided over by Lord Raglan, the 

 Lieutenant-Governor of the island, who, in the course of 

 his presidential address, gave a cordial welcome to the 

 members of the congress. He referred to the progress of 

 sanitation during the Victorian era, but pointed out that 

 England was handicapped in the hygienic struggle as com- 

 pared with Continental nations owing to our exaggerated 

 ideas of personal liberty. 



Sir James Barr, in the course of his presidential address 

 in the preventive medicine section, urged medical prac- 

 titioners to take as deep an interest in sanitation as 

 sanitarians. The health of a nation was its most valuable 

 asset, and he would like to see all his adult countrymen 

 able to handle a rifle and take part in the defence of their 

 country should occasion arise, and he would encourage 

 the military spirit as the best means of developing the 

 moral and physical qualities of the nation. He urged that 

 there should be State aid if needed for every child under 

 sixteen to be properly fed and cared for. Huge trusts and 

 millionaires were a danger to society, and part of their 

 wealth should be appropriated by the State. 



Prof. Sims Woodhead, in the section of bacteriology and 

 chemistry, delivered an address on the subject of " anti- 

 bodies," in which he traced the rise and development of 

 bacteriology, and adduced statistical evidence on the value 

 of diphtheria anti-toxin. Dr. Warrington, of Liverpool, 

 introduced a discussion on cerebro-spinal fever, in which 

 he advocated the isolation of cases and the disinfection of 

 places in which the disease had occurred. Dr. Prudence 

 Gaffitien read a paper on the causes of infantile mortality. 

 She said the high infant death-rate was due to the 

 ignorance of mothers, and advocated the prohibition of the 

 use of soothing syrups, \c. The Infant Life Protection 

 Act was worse than useless ; the State should provide for 

 the inspection of foster or nurse children. 



NO. 1967, VOL. 76] 



Prof. Hele Shaw delivered an address in the engineering 

 and architectural section on road locomotion and the 

 public health. He dealt chiefly with the new conditions 

 occasioned by the advent of motor-cars ; he admitted that 

 the public had grievances arising from dust, odour, noise, 

 and vibration, but claimed that much was being done to 

 lessen these. 



Dr. Sergeant, of the Lancashire County Council, opened 

 a discussion on the milk supply, and a resolution was 

 passed affirming the desirability of dairy regulations being 

 m;ide compulsory by the Local Government Board. 



Many valuable papers were read on notification, tubercu- 

 losis, and sanatoria. 



The social part of the congress was all that could be 

 desired, and many excursions were made to the places of 

 interest in the beautiful island. The congress dinner was 

 presided over by Lord Raglan, and there was a garden- 

 partv at Government House. 



RECENT CONTRIBUTIONS TO ELECTRIC 

 WAVE TELEGRAPHY.' 



PROF. FLEMING said that the achievements of electric- 

 wave telegraphy had not yet ceased to interest the 

 public mind. In little more than eight years from the 

 time when Mr. Marconi sent his first messages across the 

 English Channel, it had become an indispensable imple- 

 ment in naval warfare, and also a means of communication 

 between ships and the shore, greatly adding to the safety 

 of life and property at sea. .\t the present time practically 

 the whole of the first- and second-class battleships of the 

 British Navy are equipped with apparatus for electric- 

 wave telegraphy, and about 130 cruisers and smaller craft 

 as well. The Marconi Company alone have fitted with 

 their instruments nearly 100 Atlantic liners and other 

 mercantile vessels, and have an elaborate organisation by 

 which all these ships are constantly in communication 

 with the mainland during their voyage from port to port. 

 Concurrently with this, an immense amount of scientific 

 investigation has been carried on having for its object 

 further improvements and the quantitative study of the 

 phenomena. The object of the discourse was to. make 

 known some of these recent additions to knowledge. 



A cardinal feature of electric-wave telegraphy is the 

 vertical wire or wires at the transmitting and receiving 

 stations, called the antenna. At the transmitting station 

 high-frequency electric currents are set up in the sending 

 antenna, and' these create rapidly alternating electric and 

 magnetic forces in the space around, which are propagated 

 outwards from point to point with the velocity of light. 

 Hence at certain distances, called a wave-length, these 

 forces are reversed in the same way at the same instant. 

 In electric-wave telegraphy the wave-lengths used lie 

 between 200 feet and 20,000 feet or so, covering about 

 eight octaves. The measurement of this wave-length is 

 important. Prof. Fleming described an instrument of his 

 own invention, called a cymometer, used for this purpose. 

 It consists of a spiral of wire in series with a sliding 

 tubular condenser, the circuit being completed by a copper 

 bar. Across the terminals of the condenser is placed a 

 neon vacuum tube. If the bar of the cymometer is placed 

 near the transmitting antenna and the handle of the instru- 

 ment moved, its capacity and inductance can be altered 

 until it comes into tune with the antenna circuit. When 

 this is the case the oscillations in the antenna create 

 violent svmpathetic oscillations in the cymometer, and the 

 neon tube glows brilliantly. An index pointer moving 

 over a scale then shows the wave-length of the waves 

 radiated. The same instrument may be used to measure 

 the wave-length of the arriving waves. Also it can be 

 used to determine the decay of the oscillations in a train. 



In spark telegraphy the oscillations are set up in the 

 antenna by an electric discharge, and at each spark a 

 group of oscillations takes place. These may come at the 

 rate of ten to fifty groups per second, and each group may 

 contain from ten to 100 decadent oscillations. The cymo- 

 meter can be used to draw a resonance curve bj> which 

 the rate of decay and the number of the oscillations in a 



' Abstract of a discourse delivered at the Royal Institution on Friday, 

 May 24, by Prof. J. A. Fleminj. F.R.S. 



