446 



NATURE 



[March 6, 1884 



captured by Lieut.-Col. H. II. Godnin-Ansten, F.R.S., on the 

 Naga Hills, northea-.t fiontiei- of India ; but male specimens 

 had since been obtained. The author proposed to call this 

 species Corydalis asiatka. — A communication was read from 

 Dr. J. Gwyn JefTrcys, F.K.S., on the Molkisca procured during 

 the //;,'■/(('"/«?■ and /"ort'w/tJHtf Expeditions 1868-70, forming the 

 seventh part of his series of papers on this suliject. The present 

 part comprised the genera from Rissoa to Acirsa, with seventy- 

 four sp cies, of which fourteen were new to science, as was also 

 one new genus. 



Physical Society, P'ebruary 23. — Prof. F. Guthrie, presi- 

 dent, in the chair. — New Members : — Mr. E. F. J. Love, Mr. 

 James Grundy, Rev. F. J. Smith, Mr. F". R. Bawley. — Prof. 

 Silvanus P. Thompson read a paper on a new method of making 

 resistance coils. This consisted in cutting off a |.iece of the 

 wire of which the coil is to be made, long enough to give a 

 resistance some 2 per cent, higher. From the formula — 



Shunt = 



R - r 



(where A' i^ the rough resistance, and r the final resistance), the 

 value of a wire wherewith to shunt the first piece in order to 

 give the resistance required is found. A length of wire giving 

 this resistance (or, rather, about 2 per cent, more) is then cut off 

 and soldered as a shunt to the first piece. Practice shows that this 

 method is very quicU and accurate. It is useful for shunts under 10 

 ohms. Prof Thompson also described a new form of " meter 

 bridge " devised by him. The wire is 2 m. lonij, and there are 

 two wires, one of a resistance about \ ohm., the other 8'2I ohms. 

 Contact is made by one or other by a sliding contact with 

 vernier attached. This arrangement is more convenient th.in 

 the single wire meter liridge, and allows of higher resistances 

 being measured. A special switchboard with an arrangement 

 of mercury cups avoids the necessity of transposing the coils in 

 Foster's method, this being effected by shifting the contact links 

 in the mercury cups. — Mr. R. T. Glazebrook, F.R..S., explained 

 a cam or axle key devised by Mr. Shaw to effect the contacts 

 necessary to transpose the coils by a single movement. He 

 pointed out that a certain pressure was necessary to make good 

 contact with mercury. The ordinary way of making coils was 

 to double the wire, cut the bight, bare the ends there, 

 and solder a piece of copper across them, which could be 

 shifted until the resistance was got. Prof G. C. Foster 

 said that the copper links in mercury cups should rest on the 

 copper. — Prof. Foster read a paper by himself and Mr. Pryson 

 on the difference of potential required to give sparks in air. Let 

 F= this difference of potential, /= length of spark in centi- 

 metres, their experiments gave (approximately) V— 102/ -)-7'07. 

 Tables and curves of the sparking distances, potentials, and 

 electric forces in the experiments were given. The results were 

 got with brass balls I -35 centimetres in diameter, a frictional 

 machine, and a Foster absolute electrometer. When / = •142, 

 the electric force giving a spark was 15476 ; / = '284, the 

 electric force was I33'35, or less than at a shorter distance ; / = 

 497, the electric force was 131 "66; /= '9, the electric force 

 was I3S'57 ; that is, it began to rise again. — Prof G. Forbes 

 made a communication on a magnetised chronometer watch. 

 The watch slowed several minutes a day. He found the rate to 

 vary w ith the position of the watch with respect to the cardinal 

 points and also in a vertical plane. The bar of the balance was 

 magmtised and some screw nails. He traced the variation of 

 rate to magnetisation of the spring, the bar, and screws. The 

 fact that it varied with position suggested that a magnetised 

 ship's chronometer might he made which would integrate the 

 course and give a mean course. Messrs. E. Dent and Co. had 

 fitted a gold spring and a platinum iridium balance to the chrono- 

 meter, and rendered it non-magnetisable. 



Royal Meteorological Society, February 20. — Mr. R. II. 

 Scott, M.A., F.K.S., president, in the chair.— T. G. Benn, 

 Capt. C. F. Cooke, Francis Galton, M.A., F.R.S., Prof. S. A. 

 Hill, B..Sc., Capt. A. W. Jeffery, G. Paul, F.G.S., F.R.H.S., 

 R. Veevers, H. T. Wakelam, and E. Wells were elected Fellow s 

 of the Society. — The following papers were read :— The great 

 storm of January 26, 18S4, by WiUiam Marriott, F.R.Met.Soc. 

 This storm w-as remarkable for its violence and large area, 

 as well as for the unprecedentedly low barometer reading 

 at its centre. The author has prepared isotiaric charts for each 

 hour from noon on the 26th to 3 a.m. on the 27th, and by this 

 means has tracked the storm across the British Isles. The centre 

 of the ileprtssion appears to have first reached the north-west 



coast of Ireland at noon, and passed in a north-easterly direc- 

 tion over the north of Ireland and acros.s the middle of Scotland, 

 reaching Aberdeen about midnight. Its rate of progre-s was 

 therefore about thirty miles an hour. A violent gale was expe- 

 rienced all over the British Isles, the greatest hourly velocity of 

 the wind being 68 miles at Valencia at 11 a.m., 70 miles at 

 Holyhead at 2 p.m., 63 miles at Falmouth at 3 |i.m., 69 miles 

 at Armagh and 59 miles at Aberdeen at 5 p.m., 58 miles at 

 Greenwich from 5 to 7 p.m., and 76 miles at Almvick at mid- 

 night. Thunder-.torms occurred on the south-eastern side of 

 the depression, and travelled across the south of Ireland and 

 England at the rate of about thirty miles an hour. The lowest 

 readings of the barometer (reduced to sea-level) yet reported 

 were 27"32 inches at Kilcreggan at S.30 p.m., and 27'332 inches 

 at Ochtertyre, near Crieff, at 9.45 p m. In the southern part 

 of England, directly after the mmimum had occurred, there was 

 a very sudden rise in the reading of the barometer, in some cases 

 amouming to '08 inch in five minutes. From an examination of 

 previous records, it appe.ars that there has never before been so 

 low a barometer reading as 27'32 inches, so that this storm may 

 be considered as one of the most remarkable that has occurred 

 in the British Llands. — The height of the neit'ral plane of pres- 

 sure and depth of monsoon currents in India, by Prof. E. D. 

 Archibald, M.A , F.R.Met.Soc — The sunrises and sunsets of 

 November and December, 18S3, and January, 18S4, by the Hon. 

 F. A. Rollo Russell, M.A., F.R.Met.Soc. The author gives a 

 very interesting account of all the special features of the remark- 

 able sunrises and sunsets which have been observed from 

 November 8 to February 2. The following are stated to be the 

 marks distinguishing the peculiar sky-haze from cirrus : — i. It 

 is commonly much more evenly spread over Uie sky than cirrus. 

 2. It is visible (except when very dense or in the neighbourhood 

 of the sun) only abaut the time of sunrise and sunset. During 

 the day not the faintest trace obscures the clear azure, whereas 

 cirrus becjmes more distinct with more daylight. 3. When 

 actually glowing \\ith bright colour, it loses its wavy appearance. 

 4. It has no perceptible motion, unless perhaps when watched 

 through a long period. 5. It does not interfere with the clear 

 definition of the moon or brilliancy of the stars. 6. It lies, 

 almost without exception, in long streaks, stretching from 

 between south-south-west and west -south -west to between north- 

 noith-east and ea-t-north-east. - 7. Its radiant point lies, not on 

 the horizon, but far below it. 8. If both cirrus and sky-haze 

 be present, the sky-haze begins to shine with a red light soon 

 after the cirrus has ceased to glow above the western horizon. 

 When cirrus is ])resent, however, there is in general a reaction 

 of effects. 9. The sky-haze is destitute of the fibrous twists and 

 angular branches of cirrus, and, since the sunlight leaves it in 

 regular progressimi, it must be stratified at the same uniform 

 level. 10. It has always been visible on every clear day for 

 more than two months, and has been quite independent of wind 

 and weather. 



Entomological Society, February 6. — Mr. J. W. Dunning, 

 president, in the chair. — The President nominated Sir S. S. 

 Saunders and Messrs. F. P. Pascoe and R. Meldola as vice- 

 presidents for the ensuing year. Two new members were elected. 

 — Mr. P. Crowley exhibited specimens of Castnia eiiJesmia, with 

 eggs, larval galleries, and pupze. — Mr. \V. F. Kirby exhibited a 

 coloured photograi>h of an abnormal specimen of the genus 

 Samia, which had been bred by M. Alfred Wailly. — Mr. H. T. 

 .Stainton remarked on the food of the larva of Aglossa pin- 

 guinalis. — The Secretary exhil)ited photographs of the female of 

 Hypocepha'ns aymaltis, and read some notes on the subject by 

 Dr. Sharp. — Mr. F. P. Pascoe exhibited a collection of Curcu- 

 lionidie from New Guinea. — The President mide some remarks 

 on the attempt to introduce humble-bees into New Zealand. He 

 also ciUed attention to the disappearance of many common 

 butterflies and moths from the neighbourhood of Huddersfield, 

 upon which a discussion ensued, the opinion of most of the 

 speakers being that butterflies were rapidly becoming much 

 scarcer in England than they used to be. — The Secretary read a 

 report from the Committee appointed to inquire into the alleged 

 occurrence of Phylloxera in Victoria, confirming its presence in 

 that colony. — Mr. J. W. Douglas communicated a description of 

 a new species of Orthezia from Monte Cristo. — Sir S. S. 

 Saunders communicated further notes on the caprification of 

 domestic figs. 



Anthropological Institute, February 12. — Mr. John Evans, 

 F.R.S., vice-president, in the chair. — The election of Mr. Joseph 



