54^ 



NATURE 



\Oct. 6, iSa; 



pressure to the velocity of the wind. He points out that the 

 formula generally used by English and American engineers and 

 meteorologists, and which seems to have come down from a 

 preceding century, is undoubtedly very erroneous. The formula, 

 viz. / = o'CMD5 v"', is used at all altitudes and for all tempera- 

 tures, without regard to the varying densities of the air. The 

 true theoretical formula — that is, one that would hold good in 

 case of no viscosity of the air — is given at p. 302 of his " Recent 

 Advances in Meteorology " (Nature, July 14, p. 255). For 

 an average temperature of, say, 15° C, and air of the standard 

 pressure of 760 millimetres, this formula becomes / = o '00255 v"-, 

 which gives the ratio I : i "96 between the two constants, from 

 which it follows that the velocities usually deduced from pres- 

 sures should be very considerably increased. The author alsD 

 objects to the use of \h>i constant 3 which is employed in the 

 reductions of wind velocities obtained from a Robinson's anemo- 

 meter of the Kew pattern, and which is about one-fourth too 

 large, except for low relocities, as is shown by recent experi- 

 ments by Stokes and Whipple in this c luntry, and by others 

 abroad. The same journal also contains interesting articles on 

 the comparison of rain-gauge^, by F. Pike, and on tornadoes, 

 by H. Allen. The latter recommends the adoption of the term 

 "low area," or " helicone," instead of cyclone, which he thinks 

 should be applied to West Indian storms only. 



The -.-esults of rain and river observations made in New South 

 Wales and part of Queensland during 1886, published by the 

 Government Astronomer for New South Wales, contain a large 

 quantity of valuable statistics on the distribution of rain, the 

 heights of rivers, and evaporation. The number of stations in 

 New South Wales has increased from 641 in 1885 to 772 in 

 1886, yet there are many parts of the colony still unrepresented. 

 The Report is accompanied by a map, showing very plainly by 

 means of black spots of various sizes the increase in the amount 

 of rainfall as we go northwards into tropical regions, until 

 Innishowen, in Queensland, caps the list with 176 inches. The 

 greatest average rainfall in New South Wales is only 64 inches, 

 at Antony, just under a very high mountain range, and next to 

 this Port Macquarie, 60 inches. The mean rainfall for the 

 whole colony amounted to 26-04 inches in 1886, being 11 per 

 cent, more than the average for the past twelve years. 



The Meteorological Council have issued a new edition of 

 their " Fishery Barometer Manual." The first edition of this 

 work was published by Admiral FitzRoy about thirty years 

 ago, and was freely distributed by the Board of Trade to small 

 ports and fishing-stations supplied with public barometers. This 

 useful practice of supplying barometers to fishing-stations has 

 been continued to the present time, nearly 170 barometers 

 having been erected, in addition to those issued by the Roy al 

 National Lifeboat Institution. The present Manual contains 

 much additional elementary information likely to be of use to 

 the fishermen, and refers briefly to the recent advances in the 

 development of weather prediction, especially by means of daily 

 charts. Reference is also made to the telegrams now received 

 daily from America, and to the warnings issued by the New 

 York Herald Service. The Manual also contains a table show- 

 ing the distribution of gales on our coasts during fifteen years, 

 from which it appears that November is generally more stormy 

 than December, and that the maximum storminess in March, 

 which is especially marked in North-East England, entirely dis- 

 appears in South- West Ireland and South- West England. 



We had occasion recently (Nature, June 23, p. 184) to refer 

 to the active steps taken by Mr. Clement L. Wragge in pro- 

 moting the meteorological service in Queensland, and we have 

 now to record a further development by the publication of daily 

 weather charts for Australasia. The charts are drawn for 

 8 a.m. daily, giving isobars, wind direction and force, and the 

 temperature and humidity of the air. Rainfall is represented by 

 dots of various sizes, while other phenomena, such as dust-storms, 

 fog, hail, &c., are shown by appropriate symbols, and there is 

 also a synopsis of the existing weather. The charts will be of 

 great^ utility in the study of the weather of the Australian 

 colonies. 



We are pleased to notify the publication of a Monthly Weather 

 Record for the Mauritius, the first issue of which, for January 

 last, has been received. The Record, which is after the style of 

 the United States Weather Review, but without plates, contains 

 the results of observations taken at the Royal Alfred Observatory, 

 ogether with the means and extremes of temperature at four 



other stations, rainfall observations taken at fifty-five station?--, 

 observations taken at Rodrigues and the Seychelles, and ob- 

 servations taken on board ships in the Indian Ocean. The 

 Observatory of Mauritius stands on a plain near Port Louis, 

 three miles from the west coast, 179 feet above the sea-level. 

 From west-south-west through west to north there is an un- 

 interrupted view of the sea, and from north through east to 

 south-east the ground generally slopes to the summit of the 

 Piton, four miles distant, and 917 feet above the sea. Between 

 south-east and south-west there is a chain of mountains, the 

 highest peak of which bears nearly six miles due south, and has 

 an altitude of 2874 feet above the sea. Among the miscellaneous 

 observations it is noted that the tail of a comet (supposed at first 

 to be Barnard's comet) was seen on January 20, and three 

 subsequent evenings from various parts of the island. 



THE BRITISH ASSOCIA TION. 



Section A — Mathematical and Physical Science. 



On the Magnetization of Iron in Strong Fields, by Prof. Ewing, 

 F.R. S., and Mr. W. Low. Read by Prof. Ewing.— In the 

 experiments described iron was subjected to very intense mag- 

 netization by placing a narrow neck between two massive pole- 

 pieces. In this way values of magnetic induction higher than 

 those previously reached had been attained. Through the kind- 

 ness of Prof. Tait the large electro-magnet of the Edinburgh 

 University had been transferred to University College, Dundee, 

 and by its means the induction was pushed up to the value of 

 38,000 C.G.S. units. There seemed, indeed, to be no limit to 

 the value attainable, and so the neck was then turned down to 

 about one-sixth of its previous diameter, and the induction was 

 forced up to 45,000. By turning the neck still further and 

 annealing it, the highest value of 45,350 was reached. An 

 attempt was made to determine the strength of the magnetic 

 field in the immediate neighbourhood of the neck. The quantity 



~ ^ , where B was the magnetic induction, was found to 



change from 1680 in an experiment where B was 24,700, to 1420 

 in the case of the highest value of B attained. This would 

 favour the idea that the intensity of magnetization has a limit. 

 But it is difficult to be quite sure that the field in the immediate 

 neighbourhood of the neck is the same as in the neck itself. 



In order to overcome this difficulty the field in the air round 

 the neck was explored by means of three or four coils wound one 

 on top of the other. This will show if the field is varying fast 

 near the iron. If not, it would be natural to assume that the 

 field is much the same as in the iron, because in the median 

 plane there is no surface magnetism. 



On Some Points in Electrolysis and Electric Conduction, by 

 Prof. G. Wiedemann. — Before proceeding to the discussion of 

 electrolysis the author wished to congratulate the Association on 

 the appointment of a Committee to investigate this important sub- 

 ject, and further to congratulate the Committee on having Prof. 

 Lodge to direct their labours. He had read with great interest 

 the able report on electrolysis which had been some time ago 

 presented to them by Prof. Armstrong. His own communica- 

 tion would contain much that was old, and something that was 

 new. There was a difficulty in the definition of an electrolyte. 

 Some people say an electrolyte is a salt. Some say it is abinarj' 

 compound. But what is a binary compound ? It is somethingj 

 which can be decomposed into two parts. But water- free hydro-i 

 chloric acid does not conduct. Nevertheless it can be decom^ 

 posed into two parts. Whether the water plays a part in decora^ 

 position is still an open question, although Kohlrausch thinks ' 

 has shown that in very dilute solutions the water does take part.; 

 The resistance of an electrolyte is measured by the work doue 

 in the wandering of the ions. It had been said that his viey 

 was that the viscosity is proportional to the resistance. This 's1 

 not quite correctly stated. There are to be considered (i) friction! 

 of the ions in the liquid, (2) friction of the salt in the liquid, 

 (3) friction of the whole liquid on the walls of the vessel. 

 (3) may be avoided, and therefore we can omit it. The main 

 thing considered has been the friction of the ions in the liquid. 

 Kohlrausch has lately taken very dilute solutions, and can 

 only find the friction of the salts and not that of the ions 

 present here, which agrees with his theory. A difficulty in this 

 connexion is, that in very dilute solutions the impurities of tbc 



