May 23, 1878] 



NATURE 



III 



is well founded, although the observations which originally 

 suggested it have since been shown to be fallacious. Dr. Cun- 

 ningham states that the presence of Choanephora on plants 

 certainly greatly accelerates decay, but it is a cause, not a 

 consequence, of advanced putrefaction. 



Physical Society, March 30.— Prof. \V. G. Adams, presi- 

 dent, in the chair. — The following candidates were elected 

 Members of the Society :— S. Bidwell, M.A., LL.B., W. Grant, 

 E. Gurney, and J. H. Smith. — Mr. W. H. Preece described 

 Byrne's pneumatic battery and exhibited some of the results that 

 may be obtained by its means. It is especially devised with a 

 view to provide the medical profession with a portable battery 

 capable of producing a considerable amount of heat, as is 

 required for cauterising operations. The negative plate consists 

 of a very thin plate of platinum to which a lead backing is 

 soldered, and this is covered with a sheet of thick copper also 

 coated with lead, the whole being then covered with a non-con- 

 ducting varnish with the exception of the exposed platinum 

 face ; such an arrangement is found to be advantageous in that 

 it increases the conductivity of the negative plate. Two of these 

 plates are arranged to face the zinc plate as in Wollaston's form 

 of cell, and the exciting liquid consists of twelve ounces of 

 bichromate of potash, one pint of sulphuric acid, and five pints 

 of water. By using such a mixture the sulphuric acid attacks 

 the zinc and the three atoms of very loosely combined oxygen 

 exercise a depolarising effect by absorbing the evolved hydrogen. 

 A fine tube dips into the exciting liquid and is so arranged that 

 it conducts a current of air, from a small pair of bellows, against 

 the face of the negative plate ; by this means any bubbles of 

 hydrogen are, as it were, brushed off, and the current obtained 

 from a given electromotive force is materially augmented, since 

 the resistance is diminished. Mr. Preece then referred to several 

 old forms of battery in which such an agitating principle is 

 introduced, notably those of Grenet, Chutaux, and Comacho, and 

 he went on to describe a series of experiments he has made with a 

 view to ascertain the cause of the great heating and illuminating 

 effects that could be obtained with the apparatus exhibited. He 

 showed that the effects were due to the mechanical agitation of 

 the liquid on the face of the negative plate ; but whether the 

 great production of heat in the battery, and the great lowering 

 of its internal resistance were chemical, thermal, or electrical 

 effects, remains for fm-ther investigation. By means of a small 

 battery of four cells, in which the plates were 4 inches by 

 2 inches, a length of 6 inches of platinum wire. No. 18 (0*05 

 inchej), could be heated to bright redness, and much more 

 powerful effects were obtained by a large battery of ten cells 

 made by Ladd ; in this case, about 2 feet of a No. 14 (0*089 

 inches) wire were heated, and it was shown that, when connected 

 with an 18-inch inductorium, kindly lent by Mr. Spottiswoode, 

 sparks of over 17 inches could be obtained, but this length was 

 reduced to about 8 inches on stopping the current of air. A 

 similar effect was also very marked when the poles were con- 

 nected with two carbon points, the light given out when the air- 

 current was introduced being remarkably bright and steady. — 

 Mr. Preece then exhibited an ingenious method of showing the 

 vibrations of a telephone plate to an audience, which has been 

 devised by Mr. II. Edmunds. A vibrating plate is employed 

 to break contact as in Reiss's original telephone, and is intro- 

 duced into the primary circuit of a small induction coil. The 

 induced current is employed to illuminate a rapidly-rotating 

 Gassiot's tube, and, on making and breaking contact by speaking 

 into the resonator, an illuminated star is observed, the number 

 of whose arms varies vith the pitch of the note ; with a very 

 low note it may resolve itself into a single straight line. — Lord 

 Rayleigh exhibited and explained an arrangement which he has 

 employed Avith advantage in certain acoustical experiments, in 

 order to secure absolute tiniformity in the rate of rotation of an 

 axle. After referring to the mathematical principles involved 

 in such a problem, he explained that the only hope of its solu- 

 tion lay in the employment of a vibratory movement, which by 

 some suitable device must be converted into a motion of rotation. 

 The axle whose motion it is required to maintain uniform is usually 

 driven, at an approximately uniform rate, by means of a small 

 horizontal water-wheel, or, in some cases, the electro-m^netic 

 regulating apparatus presently described is sufficient by itself to 

 supply the necessary power. At equal distances round the axle 

 are arranged four soft iron armatures which successively come 

 in front of the poles of a horse-shoe electro-magnet placed in 

 ltie circuit of a four-cell Grove's battery. The current is 

 rendered intermittent by the following arrangement. Passin" 



into the body of a tuning-fork vibrating about forty times per 

 second, it leaves by a small platinum stud which is touched at 

 each vibration of the fork ; the current then traverses a second 

 small electro-magnet between the prongs, and by this means the 

 vibrations are maintained ; passing to the magnet above referred 

 to the current then returns to the battery. The velocity of the 

 axle is such that it performs about one complete revolution for 

 every four vibrations of the fork, and the exact adjustment is 

 effected as follows. If the driving power be just sufficient to 

 produce the desired speed, the armatures will be so attracted by 

 the magnet as to be exactly opposite to it at the middle of its 

 period of magnetisation, and so long as this position is main- 

 tained the magnet will not (on the whole) affect it. But if a 

 disturbance occur in the driving power the armature will be 

 displaced from its former position and will be attracted by the 

 magnet until the error is compensated. Besides the armatures 

 this axle also carries, concentric with it, a hollow metallic ring 

 filled with water, and as this possesses a certain momentum in 

 virtue of its rotation, it will act as a drag tending to check the 

 velocity in case it increases, and in the converse manner when a 

 diminution occurs. A blackened disc perforated with rings of 

 holes of various numbers also rotates with the axle and by 

 placing the eye behind the ring oi four holes and observing 

 a prong of the fork it is easy to ascertain whether the uniformity 

 is maintained, since in that case the prong will appear to remain 

 stationary. 



Entomological Society, May i.— H. W. Bates, F.L.S., 

 F.Z.S., president, in the chair. — Henry John Elwes, F.L.S., 

 F.Z.S., of Cirencester, was elected an ordinary member, and 

 Mr. Peter Cameron, jun., was elected a subscriber. Mr. 

 Dunning drew attention to the fact that the present meeting 

 marked the forty-fifth anniversary of the foundation of the 

 Society. — Mr. Distant exhibited a specimen of the Hemipteron, 

 Tetroda bilineata. Walk., as a remarkable instance of immunity 

 from the effects of damp, the same having been kept in a 

 relaxing-pan for more than four months. — Mr. Distant also com- 

 municated a paper " Notes on some Hemiptera-Homoptera, with 

 Descriptions of New Species," in which he drew attention to the 

 uncertainty of generic calculations as to geographical distribu- 

 tion, the Homoptera affording a good illustration in the family 

 Cercopida, especially the genus Cercopis. Part i of the 

 Transactions for 1878 was on the table. 



Royal Microscopical Society, May i. — H. J. Slack, pre- 

 sident, in the chair. — Four new Fellows were elected, and Pro- 

 fessor Abbe, of Jena, was elected an Honorary Fellow of the 

 Society. — A paper by Mr. Michael, on new British Cheyleti 

 was read by the Secretary. It minutely described the structure 

 and habits of the insect, and was illustrated by drawings. The 

 name proposed by its discoverer was Cheyldus flabellifer. — Mr. 

 Chas. Stewart gave a resume oi a paper which had been received 

 from Dr. Oscar Schmidt, of New Orleans, in continuation of a 

 former communication on the blood-corpuscles of Amphiuma, 

 frog, and man. The president suggested to the meeting a series 

 of experiments, which he thought might be of value in the 

 interpretation of optical images, by the examination of micro- 

 scopic drawings of Lis; ajou ; curves under various powers. He 

 also brought bafore the notice of the Fellows a species of fungus 

 which he had found infesting the leaves of the bay, but which 

 did not appear to derive its nutriment from the leaf itself. 

 After some discussion, the fungus was identified by Dr. M. C. 

 Cooke as Capnodium, Footii, which was stated to live upon the 

 honey-dew found upon the surface of the leaves of a large 

 number of trees, particularly in the autumn months. 



Institution of Civil Engineers, May 7. — Mr. Bateman, 

 president, in the chair. — The paper read was on the construction 

 of steam boilers adapted for very high pressures, by Mr. James 

 Fortescue Flannery. 



Wellington, N. Z, 



Philosophical Society, December 11, 1877. — Mr. Carru- 

 thers, C.E., the vice-president, occupied the chair. — Dr. Buller 

 read a further paper on the ornithology of New Zealand. 

 Among the species treated of were the Kaka parrot, with 

 an interesting account of the Maori mode of trapping it 

 by means of decoy birds ; the two species of migratory 

 cuckoo, with observations on their parasitic habits ; the black 

 fantail, the occurrence of which as far north as Auckland has 

 been communicated by Mr. Cheesman ; the knot ( Tringa canutus) 

 which has lately been met with in this island ; the sandpiper 

 {Limnocinchis acuminatus), and many others. Among the latter 



