November 9, 1893] 



jVA TURE 



47 



investigation, the subject is treated geometrically at considerable 

 length. Prof. Minchin showed that the impedances might be 

 represented by two hyperbolas, having /- as abcis^oe and the 

 squares of (he impedances as ordinal^. These could be readily 

 constructed from the data given. A line representing the 

 primary inductance drawn on the same diagram intersects one 

 hyperbola, showing that the impedance has always a maximum 

 value. By a simple construction the phase angle between the I 

 primary and secondary currents could be determined for any | 

 given conditions. Dr. Sum[)ner observed that increased iai- ! 

 pedance on closing the secondary necessarily meant a decrease | 

 in the lag of the primary current behind the primary P.D. Mr. j 

 Blakesley was pleased to see the geometrical method of such 

 service, and thought it much simpler than the analytical one. 

 The reason why increased impedance on closing the secondary 

 of ordinary transformers had not been noticed was because their 

 lag angles were very large. In a figure published some 

 3-ears ago to represent the actions of transformers, the 

 angles he had chosen were such as would make the 

 primary impedance increase on closing the secondary. Giving , 

 an expression connecting the primary currents on open 

 and closed secondary respectively, he now showed that 

 to get increased impedance, the sum of the lag 

 angles in primary and secondary must exceed 90°. To get 

 large power in the secondary the primary lag should be nearly 

 90°, and the secondary about 45'. He also pointed out that 

 some of the figures in thp paper might be simplified considerably. 

 Prof. Perry said he had long had the impression that if a suffi- 

 ciently small current were taken from the secondary, increased 

 impedance would be observable in all cases, and he quoted 

 some numbers he had given in the Phil. Mag. for 1891, show- 

 ing a decided increase. Mr. Rimington, in reply, said he was 

 not aware that the effect he had now brought forward had been 

 observed previously. The result was completely worked out 

 analytically before using geometrical methods. — Mr. \V. B. 

 Croft showed "Two lecture-room experiments.' One, on 

 " The Rings and Brushes in Crystals," was performed by very 

 simple apparatus in two ways. In the first, a bundle of glass 

 plates was used as a polariser, and a Nicol prism as analyser. 

 When a Nicol could not be conveniently obtained, a glass plate 

 •could be used as a reflecting analyser. For a convergent system 

 two gla'ss card-counters were used, the crystal being placed be- 

 tween them. Very good results were produced by this simple 

 apparatus. In the second arrangement the crystal was placed 

 on the eye-piece of a microscope 'whose objective was removed), 

 and covered by a tourmaline. On reflecting light up the tube 

 by means of a piece of glass held at the proper angle excellent 

 results were obtained. Another experiment, on " Electric Radia- 

 tion in Copper Filings," was similar to those described by Dr. 

 Dawson Turner at the Edinburgh meeting of the British Asso- 

 ciation. A battery, galvanometer, and glass tube containing 

 copper filings were joined in series. Under ordinary circum- 

 stances no current passed, but immediately an electric spark was 

 produced by an electric machine many feet away, the galvano- 

 meter was violently deflected, and remained so until the tube 

 was tapped. On trying different materials, aluminium and 

 copper seemed about equal, but iron not so good ; carbon 

 allowed the current to pass always. Prof. Minchin said the 

 phenomena were strikingly like those exhibited by his " impul- 

 sion cells," for the moment a spark passed, even at a distance of 

 130 feet, they became sensitive to light. Very minute sparks were 

 capable of producing the change, but by adding capacity to the 

 sparking circuit the effect could be greatly modified. Replying to 

 a question from Mr. Rimington, he said the change was due to 

 electromagnetic vibrations, and not to light emitted by the sparks. 

 jNIr. Blakesley inquired if lengthening the sparks produced 

 greater effect on the copper filings. Mr. Lucas asked if the 

 resistance of a tube ever became infinite again if left for a long 

 time. In reply, Mr. Croft said the current sometimes passed 

 before the spark actually occurred between the knobs. He had 

 not left tubes for very long, and had not found the resistance 

 reappear without tapping. 



Royal Microscopical Society, October iS. — A. D. 

 Michael, President, in the chair. — Mr. J. G. Grenfell described 

 some marine diatoms, recently found at Plymouth, belonging to 

 the genera Mdonra and Surirella, which were of interest 

 owing to the presence of pseudopodia. Mr. A. W. Bennett 

 objected to the term pseudopodia being applied to these pro- 

 cesses unless it could be shown that they were actual prolonga- 

 tions of the internal protoplasm. Mr. T. Comber said that 



KO. 1254, VOL. 49] 



Prof. Grunow was of the opinion that the processes were spines. 

 — Mr. E. M. Nelson exhibited and described a new model of a 

 microscope by Messrs. Watson. — Mr. F, Chapman read 

 Part V. of his paper "On the Foraminifera of the Gault of 

 Folkestone.' — Prof. Bell gave a resume of a paper by Dr. 

 R. L. Maddox, " On Progressive Phases of 3'//ri7/«;« tWw/awi." 

 The author had traced the development of this organism, and 

 had discovered some points which appeared to be entirely new 

 in the history of bacteria. 



Paris. 



Academy of Sciences, October 30. — M. de Lacaze-Duthiers 

 in the chair. — The grape vine harvest of 1893 ^""l ^^^ produce 

 of the Camargue, by M. Chambrelent. In spite of the severe 

 drought the vineyard-; of the Gironde have given the richest 

 yield in the century. Tliis has been due to a unique combination 

 of favourable circumstances during their development. The 

 facility with which they withstood the drought may be attri- 

 buted to the fact that vine-leaves have a peculiar power of absorb- 

 ing dew, which has been very abundant. This year has also 

 witnessed the earliest date of harvest known in the century. In 

 1822 it took place on August 31, whilst this year it was eight 

 days earlier. The quality of the harvest, which improves with 

 the quantity, may he expected to prove very good. — On the 

 application of sound vibrations to the analysis of mixtures of 

 two gases of different densities, by M. E. Hardy. The 

 apparatus, called the formenephone, consists of two organ 

 pipes, one of which is filled with pure air, the other contain- 

 ing themixture of gases to be analysed. The pipes are of the 

 same dimensions, and give the same note when blown under the 

 same circumstances. If one of them is filled with air contain- 

 ing I per cent, of formene, the unison is disturbed and one beat 

 is heard every three seconds. With 2 per cent, there are 

 three beats in two seconds, with 3 per cent, two beats per 

 second, and so on. Similar results may be obtained with car- 

 bonic acid as an impurity. The figures given apply to pipes 

 sounding C4. For mixtures whose density closely approaches 

 that of air Cg is more suitable. Each determination is finished 

 in a few seconds. The apparatus is well suited to the determi- 

 nation of the amount of fire-damp in mines. — Observations of 

 Comet Brooks ( 1S93, Oct. 16) made at the Algiers Observatory 

 by MM. Rambaud and Sy. — Observations of the sun made at 

 the Lyon Observatory ^Brunner equatorial) during the first half 

 of 1893, by M. T. Guiilaume. This is a summary of the obser- 

 vations made of sunspots and faculi^, with particulars of their 

 positions and areas. — On a new theorem of mechanic-, by M. 

 N. Seiliger. — On carboxyl derivatives of dimethylaniline 

 (dimethylamidobenzoic acid) by M. Charles Lautb. — On the 

 baking temperature of bread, by M. Aime Girard. 

 Numerous experiments have proved that 101° C. is the 

 normal temperature in the interior of bread and biscuit 

 during baking if the product is to be satisfactory. — 

 Study of the reproduction of wasps, by M. Paul 

 Marchal. Careful observations of the physiological function of 

 the workers, miscalled neuters, of a common wasps' nest have 

 proved parthenogenetric reproduction by the workers, withou: 

 the cooperation of the males, and the exclusively male sex of 

 the individuals thus produced. It appears that there is a 

 division of labour between the queen, who produces mainly 

 females and workers, and the workers themselves, which are 

 only capable of producing males. — On the localisation of the 

 active principles in Trotuohim, by M. Leon Guignard, In the 

 Tropxolum family, all the organs enclose myrosine, localised 

 in cells distinct from those which contain the glucoside, whicli 

 it decomposes to produce the essence. The latter does not pre- 

 exist in the tissues and cannot be formed without the interven- 

 tion of the ferment. The family shows in this respect a 

 complete analogy with the Crucifers and Capparideas. — On 

 the existence of gismondine in the geodes of a basalt 

 of the environs of Saint-Agreve (Ardeche), by M. Fer- 

 dinand Gonnard. — Fractures of the coal measures of southern 

 Chili, by M. A. E. Nogucs. In the lignite region extending 

 from the' Bay of Talcahuano to Lebu, there is found a large 

 fault running from east to west, which it is proposed to call the 

 Lebu-fault. To the north of this fault the strata incline towards 

 the west ; to the south, they incline towards the east. Between 

 San Rosendo and Lebu may be traced a system of parallel north - 

 to-soulh faults which have affected the older strata; a system o 

 parallel east-to-west faults, which have dislocated the arenaceous 

 lignite territory ; and a system of secondary faults, which have 

 brought about changes of level in this same formation. — General 



