no 



NA TURE 



\_May 29, 1879 



been in weak health, left England in November last year, in 

 H.M.S. Boadicea, for a holiday cruise to the Cape, and he died 

 from dysentery on the 4th inst., at Simon's Town. We defer 

 further notice of Mr. Froude's life and work till next week. 



Another advance of the greatest importance has been made 

 by the U. S. Signal Service in the department of practical meteoro- 

 logy. In the Daily Graphic for May 9, published in the afternoon 

 at New York, is a map of the principal portion of the United 

 States, with the weather conditions of the same morning. The map 

 gives in distinct outline the lines of equal atmospheric pressure 

 and of the temperatures over the United States, with the pre- 

 vailing directions of the wind and the general weather conditions. 

 By the aid of this map, which it is proposed to make a regular 

 feature of the Graphic, any one can form a fair idea of the 

 weather changes in any specified locality for some days to come. 

 The observations indicated in the map were made at all the 

 signal stations of the U.S. Government at thirty-five minutes 

 past seven on the morning of the 9th, and having been collated 

 at the central office in Washington at nine o'clock, were 

 transmitted specially by telegraph to the Graphic by ten 

 o'clock. All the details of the map have been carefully con- 

 sidered and are easily intelligible to any reader after a little 

 study. The importance of this step cannot be overrated, and 

 we only wish we saw the Pall Mall and other evening papers 

 following the excellent example of their New York contem- 

 porary. 



Prof. Asaph Hall has been elected a corresponding member 

 by the Paris Academy of Science to fill the place in the astro- 

 nomical section vacant by the death of M. Santini. 



There is being erected at Meudon a large construction in 

 connection w ith the Physical Observatory, where a large refract- 

 ing telescope will be fitted up. During the time that the works 

 are being carried on M. Janssen continues his solar photography 

 on the site where his instruments have been established, in a 

 part of the old Chateau. The diameter of the photographs 

 obtained by direct operation is now 50 centimetres, and the time 

 of exposure to solar radiation diminished to -j-touth of a second. 

 The interval of time between two successive operations has 

 been reduced to two minutes by the application of the revolver 

 system. Although the two images may represent the surface 

 of the sun at periods so near each other, M. Janssen has dis- 

 covered that there is always a striking difference in the two 

 images. It must be considered as proved by these observations 

 that no spot on the sun can be regarded as being in a state of 

 quiescence, even during so short a period, and that the changes 

 are important enough to be perceived at the distance of the sun 

 viewed from the earth, although the smallest spot observable 

 must be regarded as having a surface larger than the whole of 

 France, a second of arc on the sun being equal to the distance 

 between Paris and Marseilles. 



Admiral Mouchez has almost completed his museum of 

 astronomy in one of the rooms of the Paris Observatory. 

 Exclusive of the portraits of Bouvard, Arago, Leverrier, Cassini, 

 and other directors, a series of the principal celestial objects has 

 been painted on the walls by talented artists. In the middle is a 

 glass case in w hich a number of instruments used by astronomer^ 

 of former ages are exhibited. M. Mouchez intends to publish a 

 monthly pericjdical, which will be called Journal d Astronomic. 

 A part will be reserved for the original communications of the 

 astronomers of the Paris Observatory, and part devoted to 

 reviewing foreign astronomical periodicals. 



The Paris Anthropological Society has recently awarded 

 prizes as follows : — The Godard Prize (500 francs and a silver- 



gilt medal) to Dr. Le Bon, for a work on the development of 

 the cranium according to civilisition, age, and sex ; two honour- 

 able mentions (with bronze medals) to M. Ujfalvy, for the first 

 volume of his "Journey in Turkestan," and M. Zaborowski, for 

 his "Manual of Prehistoric Archeology ;" the prize in French 

 Ethnology to Dr. Chervin, for his statistical works ; and honour- 

 able mention to M. Riviire for his prehistoric researches. • 



Sir William Thomson gave some valuable evidence on 

 Friday before the Select Committee engaged in considering the 

 subject of the electric light. He said that whereas one-horse- 

 power of energy would only produce i2-candle gas light, it 

 might produce 2,400-candle electric light. "The upshot of the- ^ 

 experiments made at the factory of Messrs. Siemens, at Wool- ^ 

 wich, and at the natural philosophy class of the University of 

 Edinburgh, was that, allowing the practical estimate of one- 

 horse-power applied in driving the engine, it had produced 1,20a -.aH 

 candles of actual visible electric light, half the gross energy going ^ 

 to produce the light while the other half was lost in heating the 

 machine and the wires. As the electric light was such an 

 economical producer he anticipated that it had a great and im- 

 mediate future before it. He believed before long it would be 

 used in every case where a fixed light was required, whether in 

 large rooms or small ones — even in passages and staircases of 

 private dwellings. There was immense promise in the actual 

 work carried out by practical men in the present day. There 

 was a prodigiously greater economy in the transmission of 

 mechanical force into energy in the case of the electric light than 

 in the case of gas. With regard to regulators for the electric 

 light, he had seen one the previous day — the Siemens regulator — 

 which gave a steady, pure, and quiet light. The electric light was 

 especially adapted for being placed high where it illuminated a 

 wide area. It might be put upon an iron pole raised 60 feet 

 high, or the old French plan of swinging a lamp on a wire from 

 one side of the street to the other might be followed with advan- 

 tage. Such a plan would be useful in doing away with the 

 necessity for opal globes, which destroyed a large quantity of 

 the illuminating quality of the light. Indeed, he was surprised 

 that these globes had ever been used, wasting as they did 50 or 

 60 per cent, of the illuminating power. He considered that the 

 advantages of using the electric light within buildings would be 

 very great, because of the small effect it would have when com- 

 pared with gas in heating and vitiating the atmosphere. In the 

 case of electricity, the waves of light only became converted into 

 sensible heat, not in the air, but on the ceiling or walls and floor 

 of the room after they had done their work. With regard to the 

 subdivision of the light, according to practical experiments, if 

 the same amount of energy that was used in producing one 

 large light was employed in producing ten feebler lights, 

 none of those lights gave one-tenth of the amount of illu- 

 mination of the one large concentrated light. Still there was 

 nothing mathematically impossible in the matter, and it was 

 quite possible that a plan of subdivision might be found by 

 which the ten feebler lights would give a sum of illumination 

 equal to that of the one larger light. He considered that the 

 electric light as now developed was fit for use in large rooms. 

 He was also of opinion that a great deal of natural energy which 

 was now lost might be advantageously applied in the future to 

 lighting and manufactures. There was a deal of energy in 

 waterfalls. In the future, no doubt, such falls as the Falls of 

 Niagara would be extensively used — indeed, he believed the 

 Falls of Niagara would in the future be used for the production 

 of light and mechanical power over a large area of North 

 America. The electricity produced by them might be advan- 

 tageously conducted for hundreds of miles, and the manufactories 

 of whole towns might be set in motion by it. Powerful copper 

 conductors would have to be used — conductors of a tubular fprm 



