=?6o 



NA TURE 



[Al'RIL 12, 1894 



water and sea-floor is restricted to relatively few species ; a 

 marked contrast to the bacterial contents of rivers, lakes, &c. 



We have receive! from the Berlin Aquarium Society a copy 

 of the regulations and of several other documents relating to 

 the Marine Zoological Station established in 1891 by that enter- 

 prising body at Rovigno, in the Adriatic. Primarily intended 

 as a source of supply of living marine animals to the Berlin 

 Aquarium, the Rovigno station is also equipped for the pur- 

 poses of scientific research with all the ordinary apparatus and 

 reagents of a biological laboratory, a Jung microtome, a circu- 

 lation of pure sea-water, a steam-launch, and a growing library. 

 The site of the laboratory seems to have been very carefully 

 cho?en with a view to the purity of the sea-water supply, several 

 available and nearer sites having been rejected owing to the 

 existence of an excess of fresh- water or some other source of con- 

 tamination. The fauna is rich and varied, the climate mild and 

 genial ; and Rovigno, without pretending to be in the van of 

 modern culture, seems to be a pleasant and hospitable town, 

 not least among its attractions being an excellent light wine at 

 sixpence per litre ! No charge is made for working in the 

 laboratory, and permission may generally be obtained upon 

 application to the Berlin Aquarium. The Rovigno staff is 

 always willing to supply information as to lodgings in the 

 town, and can also put up four naturalists at a time in the 

 laboratory house at the moderate charge of one shilling per day. 

 Altogether, British naturalists in search of fresh seas and 

 creatures new may well consider the generous claims of the 

 Rovigno station. 



The Royal Meteorological Institute of the Netherlands has 

 issued its forty-fourth Jaarhoek, containing observations made 

 thrice daily at a number of stations, and hourly at four places. 

 A considerable improvement has recently been made in the 

 Dutch meteorological service by the adoption of the inter- 

 national scheme of publication recommended by the meteoro- 

 logical congresses ; but it has already been pointed out by Dr. 

 Hellmann that a further improvement might be made by taking 

 the evening observations at one hour, instead of jh., 8h., or 

 10b. p.m. as at present. There are few countries that can 

 boast of a longer continuous series of trustworthy observations. 



The Rev. S. Chevalier, Director of the Zi-ka-wei Observa- 

 tory, near Shanghai, has published a detailed discussion of the 

 typhoons of 1892, based on observations made in the months of 

 July, August, and September, on ships and at land stations. 

 The pamphlet contains synoptic charts and valuable data for 

 the study of the behaviour of these storms, and also a chapter 

 devoted to the examination of some important questions relat- 

 ing to them. It has been stated that an area of high pressure 

 always precedes, by some days, the arrival of a typhoon, but 

 out of five of the principal typhoons of the year 1892 the author 

 finds that only one was preceded by an anticyclone. Another 

 important question is that of the convergence of the winds to- 

 wards the centre of the cyclone. The observations show that the 

 winds do converge towards the centre, not only in the exterior 

 zone of the typhoon but also in the whirl itself. With regard 

 to determining the distance of the centre of the typhoon accord- 

 ing to the fall of the barometer, the conclusion arrived at is 

 that while the fall is more likely to give an idea of the distance 

 of the centre than the absolute height, the figures show clearly 

 that no exact measure of the distance can be obtained by that 

 means. An empirical rule for determining the rate of progress 

 of the centre, formulated by Captain Fournier, has been found 

 useful in some cases. An explanation of this rule and examples 

 of its application are given in the pamphlet in question. 



The determination of the pitches of very high notes appears 

 lo be greatly facilitated by an arrangement recently worked out 



NO. 1276, VOL. 49] 



by F. Melde, and described in the current number of IViede- 

 nianns Annalen. The extreme difficulty of distinguishing 

 between the various octaves of the same high note, led Mr. 

 Melde to abandon the use of the ear altogether, and to apply 

 the microscope to the more reliable vibrographic method. To 

 prepare the plate for taking the traces, he melted a mixture of 

 stearine and olive oil, and spread it out with the finger, thus 

 obtaining a thin layer with a delicate ridged structure, which 

 could be renewed by simply passing the finger over it. The 

 tracing point chosen was a short piece of hair from the violin 

 bow. By attaching one of these to each of the vibrating 

 bodies, say a high tuning-fork an 1 a rod vibrating longitudinally, 

 and drawing the glass plate rapidly over the two tracing points, 

 wave carves were obtained whose periods could be easily com- 

 pared under the microscope. The tuning-forks were set 

 vibrating preferably by means of a we", glass rod rubbing over a 

 piece of cork attached to one of the prongs. This manner of 

 exciting vibrations offers several advantages over that of the 

 violin bow. The sounds produced are much more in'ense, they 

 can be produced by either hand, or two at a time, and the rod 

 is less perishable and less likely to get into the w.iy of the other 

 apparatus. 



An interesting paper on the difference of potential between 

 an aqueous and alcoholic solution of the same salt, by A. Cam- 

 petti, appears in the Alti dell' Accadeviia di Torino, vol. xxix. 

 The author has determined the difference of potential which 

 exists at the suiface of separation between an alcoholic and 

 aqueo.is solution of various salts, such as ammonium chloride, 

 liihium chloride, calcium chloride, &c., which are soluble both 

 in water and alcohol. The dilTerence of potential was measured 

 by means of dropping mercury electrodes, which have given 

 satisfactory results in the hands of Pascheri. The measurements 

 were undertaken with a view to seeing whether the numbers 

 obtained by experiment agreed with the values obtained 

 from Planck's formula, which gives the difference of potential 

 in terms of the concentrations and ionic velocities of the elec- 

 trolytes. The author finds that the formula is not applicable, 

 but that in the case of two different solvents it is necessary to 

 suppose there is some additional force coming into play, which 

 is not taken account of in Planck's equation. He intends, 

 in a subsequent paper, to give the results he has obtained on the 

 ionic velocities in different solutions. 



In connection with the question as to the point of application 

 of the mechanical force experienced by a conductor conveying 

 a current in a magnetic field, M. Pellat has communicated a 

 second paper to the Societe Francaise de Physique, in which 

 he comes to an opposite conclusion to that given in a former 

 paper on this subject (see note in Nature, March 22). The 

 error in the former paper was due to the omission of a term in one 

 of the equations. For if we consider a gramme ring at rest and 

 on short circuit, and suppose that the field magnets are rotating, 

 the wire of the armature is traversed by an induced current 

 which warms it up, and it would be necessary to withdraw a 

 quantity of heat Q to bring it back to its initial condition. If 

 we consider the armature alone as a system, the electromagnetic 

 forces, in this case, perform no work, and this heat com- 

 municated to the ring can only be due to energy supplied to the 

 ring by the action of the electromagnetic forces, the product of 

 an electromotive force by the quantity of electricity displaced 

 being the equivalent of work, and this product may be called the 

 work of the electromotive forces ; it is work done on the system, 

 and calling it c we have e - JQ. The same takes place when 

 the ring is replaced by the Foucault disc. Consequently, in the 

 case when the disc is in movement, the field magnets being 

 fixed, it w is the work done by the weights which drive the 

 disc, and x that done by the electromagnetic forces, we get 



