NA TURE 



[Jan. 15, 1874 



ceding information, the Nivutical Almanac gave, first for 

 every day, and from i 861 for every two days, the epheme- 

 rides of all the planets for the time of their passing the 

 meridian of Creenvvich, information which French astro- 

 nomers would have been happy to find in the Conuaissaucc 

 dcs 7"tv;//j- for the meridian of Paris. Let us add, more- 

 over, that the posiuons of Neptune were only given in 

 the Coimaissance dcs Temps in 1861 (for 1863), while 

 they were in the Naidical Almanac from 1857 (for 

 1861). 



It was also in this same year, 1863, that the Connais- 

 sance dcs Icmps gave for the first time the values of the 

 constants of Bessel, intended to transform into apparent 

 positions the mean positions of the stars given by the 

 catalogues ; as well as the elements of the occultations, 

 accorchng to Besse\, in a form which enabled voyagers to 

 calcidate°for the very place where they happened to be, 

 the principal circumstances of the phenomena. The 

 Nautical Almanac had published all this since 1834. 



In 1864, the positions of the sun, which for many years 

 were calculated with the tables of Delambre, recon- 

 structed in part by M. Mathieu, were published accord- 

 ino- to the tables of M. Leverrier ; the same was done for 

 the positions of Mercury, and in the following year for 

 those of Venus and Mars. The Nautical Almanac had 

 used the tables of M. Leverrier since 1S60 for the sun and 

 Mercury (/l///w«r?i- for 1864), since 1861 for Venus (.-Y/- 

 manac for 1S65), since 1862 for Mars (Almanac for 1866). 

 On the other hand, the Connaissancc dcs Temps for 1864 

 appeared in February 1863, and consequently six months 

 z.h&x'C^Q Nautical Almanac iox 1866. Finally, the C<v/- 

 naissancc dcs Temps for 1864 contained the rectilinear 

 co-ordinates of the sun referred to the plane of the 

 equator ; they are found in the Nautical Almanac from 

 1849. 



This collection of reforms raised considerably the value 

 of the Connaissancc des Temps, which, it was unani- 

 mously agreed, had fallen very low as compared with 

 foreign eptiemerides. The reform accomplished in France 

 in 1864 was analogous to that of the Jahrbuch in 1829 

 and of the Nautical Almanac in 1830. But even at the 

 present time the Connaissancc dcs Temps does not con- 

 tain any ephemeris of Ceres, of Pallas, of Juno, nor of 

 Vesta, which has appeared in the Nautical Almanac and 

 the jfahibuch since 1830; nor of any of the numerous 

 small planets discovered since 1845, for which the other 

 two works pubhsh a supplement each year. Yet for a long 

 time past the continued observation of these telescopic 

 planets has formed one of the most important occupations 

 of most of the observatories. 



In 1870 the direction of the Connaissancc des Temps 

 passed into the hands of Puiseux, who, however, kept it 

 for only a very short time. His period of office, never- 

 theless, was marked by an important improvement. He 

 indicated, by a figure in the proper place, the day on 

 which, in consequence of the difference of length between 

 the sidereal day and the mean solar day, each star passed 

 twice across the superior meridian of Paris. This was a 

 sad omission ; such an indication is found in the A^autical 

 Almanac for 1822. 



At present the direction of the Connaissancc des Temps 

 is entrusted to M. Lrewy ; Mr. Hind has been superin- 

 tendent of the iV«7<//(7!/ .4 ////(;«i7t Office since 1S53, and 

 Herr Fcerster succeeded, in 1864, the celebrated Encke in 

 the direction of the Jahrbuch of Berlin. 



TELEGRAPHING EXTRAORDINARY 



AT the Telegraph Office, Washington, on Dec. 11, 1873, 

 an experiment was carried out in the presence of 

 Mr. Creswell, the Postmaster-General of the United 

 States, the practical results of which will be of immense 

 importance as regards the future of telegraphy throughout 

 the world. 



On that occasion the president's last annual message 

 of 11,500 words was transmitted from Washington to 

 New York, a distance of 290 miles, over a single wire in 

 22); minutes, the speed obtained being over 2,500 letters 

 per minute. 



At New York the message was delivered from the auto- 

 matic instrument printed in bold type in presence of the 

 Postmaster of New York. This achievement in tele- 

 graphy is the more remarkable as the principle involved 

 is not new, but was well known in 184S. The experiments 

 made at that date were practically without result. By the 

 new American combination of chemistry and inechanism 

 the speed is apparently almost unlimited, messages at 

 the rate of 1,200 words, or 6,000 letters, a minute being 

 afterwards transmitted with equally satisfactor)- results. 



Hitherto the speed attainable over circuits of similar 

 length in this country by the Wheatstone automatic 

 system, at present in use for the " high speed " service by 

 the Postal Telegraph Department, does not exceed 200 

 letters a minute. 



The new American instrument has a great advantage 

 in the extreme simplicity of its construction, mechanical 

 detail giving place to chemical action. One important 

 result of this experiment is that it demonstrates that 

 hitherto the speed of transmission of electric currents 

 through a metallic conductor has been restricted from 

 mechanical imperfections in the mechanism of the re- 

 cording or receiving instrument, and that by the substi- 

 tution of chemical decomposition for mechanical action, 

 an almost unlimited speed of transmission may be 

 obtained. It is to be hoped that this new transmitting 

 and recording instrument may be the agent by which 

 our present tarift'of is. for twenty words, may be reduced 

 to bd., or less, for a similar message. Scientific progress, 

 practically applied, is an heirloom to a nation. 



NOTES 



Mr. Henry Lonsdale is preparing a biography of John 

 Dalton, the great chemist, and would be glad of any letters or 

 other aid in his important work. 



At the meeting of the Paris Academy of Sciences held on 

 Monday, January 5, M. Fremy was elected president for the 

 ensuing year, and MM. Chasles and Decaisne were elected to 

 serve on the central committee. 



A COMMITTEE, consisting of Lord Cathcart, Mr. C. While- 

 head, Mr. Jabez Turner, Mr. Wakefield, Mr. Brandreth Gibbs, 

 Mr. J. Bowen-Jones, Mr. W. Carruthers, F.L.S., and Mr. J. 

 Algernon Clarke, appointed Ijy the Royal Agricultural Society 

 to carry into effect the suggestions of the judges of the potato 

 disease essays held a meeting on Monday at Hanover Square, 

 They «'iU recommend the Council to offer three prizes of 100/. 

 e.ach for disease-proof potatoes. Competitors will probably be 

 required to send in one ton of eacli variety fiy the middle of 

 February. Each sample will be distributed among gi'owers in 

 many different parts of England, Wales, Scotland, and Ireland; 

 and the produce of potatoes which resist disease during the first 

 year's trial will be tested for two years longer. With a view of 

 encouraging the production of new v.irleties, handsome prizes 

 are to be offered also for disease-proof sorts raised from potato 

 plums to enter into competition in the spring of 1S79. The 

 terms and conditions will be decided upon at the next meeting 

 of the Council. 



The Lndian Museum, as it now stands, situated on the 

 highest story of the India Office, has been found to be useless 

 for all the purposes for which it was intended. It has therefore 

 been resolved to erect on the plot of vacant ground in Charles- 

 street, directly opposite the India Offices and facing St. James's 

 Park, a new museum and public library. To this building, 



