March 8, 1900J 



NA TURE 



451 



i'KOF. A. Heilprin points out in the Scientific American that 

 1 source of doubt which attaches to the Nicaragua Canal and in- 

 volves the question of permanency is furnished by the level of 

 I .ake Nicaragua— the fountain-head of the San Juan River, and 

 he summit and feeder of the proposed canal. The regulation of 

 \s level is necessarily a matter of absolute or vital importance 

 > the canal. The very elaborate measurements of American 

 Liigineers that have been made during the last fifteen years indi- 

 cate for the surface of the lake an average elevation at this time 

 of approximately 105 feet above tide. This is nearly twenty per 

 cent, less than the value obtained some years ago ; and as the 

 result of a consideration ot the subject, Prof. Heilprin thinks it 

 would not be safe to assume that the earlier measurements of the 

 lake were erroneous. He thinks it more probable that the level 

 of Lake Nicaragua is inconstant, and that the surface has dropped 

 15 to 20 feet in a period of little more than half a century. 



The effects of the great dynamite explosions at Avigliana 

 (near Turin), on January 16, are described by Dr. M. Baratta in 

 a privately printed pamphlet. About 400 kg. of nitro-glycerine 

 and 12,000 kg. of dynamite and gun-cotton were blown up. 

 The first and stronger explosion, though it lasted little more 

 than a second, presented three maxima of intensity, due pro- 

 bably to the successive explosions of magazines a hundred metres 

 from that in which the nitro-glycerine was stored. Owing to 

 the situation of the manufactory, the zone of greatest damage 

 was very small ; that in which windows were almost totally 

 destroyed extended to a distance of 5^ km. ; doors and windows 

 were made to rattle as far as Crescentino (60 km. distant) ; and 

 the sound of the explosion was heard at Pavia (140 km.), Varzi 

 (145 km.) and Lugano (160 km.). 



We have received from Prof. Albin Belar the first part (for 

 [muary 1900) of a monthly report on the earthquakes recorded 

 the seismological observat ory of Laibach, of which he is the 

 aiector. Some brief notices of earthquakes which occurred in 

 iher countries during the same month are also included. As 

 Laibach is one of the most important earthquake centres in 

 Europe, the reports issued from the observatory cannot fail to 

 be of considerable interest and value. 



An interesting lecture was recently delivered by Dr. J. M- 

 I'ernter before the Austrian Meteorological Society, upon some 

 extensive experiments made in several Italian provinces last 

 year for the prevention of damage by hail by gun-firing. The 

 lea is an old one, but the apparatus, constructed by Mr. A. 

 -Jger, burgomaster of Windisch-Feistritz, Steirmark, consisting 

 f a mortar provided with an iron funnel about six feet long, 

 ppears to have obtained very satisfactory results. The experi- 

 ments were witnessed by Dr. Trabert, of the Vienna Meteoro- 

 logical Office, and it was found that a timely commencement of 

 the firing effectually prevented the fall of hail, whereas in 

 districts where the experiments were not made much damage 

 was^caused by hail-storms. The immunity from damage may 

 have been due to the force of the air- whirls, the sound of which 

 could be heard for twenty or thirty seconds, or to the fact that 

 the electrical discharge between the earth and the clouds was 

 <|uietly effected by the shooting, and thus the chief factor of 

 liail formation removed. 



The Victor Meyer Memorial Lecture, delivered by Dr. T. E. 



Thorpe, F.R.S., before the Chemical Society on Februarys, 



- published in full in the March number of Xht Journal oi the 



-iiciety, with an excellent portrait of the lamented investigator. 



Many scientific societies, both abroad and at home, issue their 



ublications in so tardy and irregular a manner that the ex- 



inple of the Chemical Society in publishing the yijMrwa/ regularly 



very month might be followed with advantage. Few societies 



• ublish discourses so elaborate as that of Dr. Thorpe's within 



NO. 1584, VOL. 61] 



three weeks of their delivery. It is unnecessary for us to do 

 more than briefly refer to the address, as a notice of the work 

 and personal characteristics of Vict^ Meyer appeared in these 

 columns in September 1897, shortly after his death (vol. Ivi. 

 p. 449). As a friend of nearly thirty years' standing, and as 

 one who studied with him under Bunsen, Dr. Thorpe was in 

 the position to give an excellent account of the remarkable 

 services Victor Meyer rendered to science during his life. 

 Meyer contributed to the literature of chemistry, either alone 

 or in conjunction with his pupils, upwards of three hundred 

 memoirs and papers. As an investigator, he was original as 

 well as active ; as the director of a large chemical laboratory 

 and a laboratory teacher, he worthily followed in the footsteps 

 of Bunsen ; and, as a lecturer, he was brilliant as well as lucid. 

 Dr. Thorpe's lecture is a worthy appreciation of the genius of 

 a gifted man who devoted his energies to the advancement of 

 science. 



Mr. T. Southwell contributes to the Zoologist his annual 

 account of the seal and whale fishery. From this we learn that 

 the pursuit of the Greenland Bight Whale was fairly successful 

 during the past season ; a remarkable feature being that although 

 none of these Cetaceans were seen in the Greenland seas, they 

 were comparatively plentiful in Davis Strait and the adjacent 

 waters. The majority of the twenty-eight whales taken were of 

 good size, some of them being of very large dimensions. During 

 the year the price of whalebone fell to 1400/. per ton, although 

 more is now asked ; in past years more than 2500/. per ton has 

 been realised. Mr. Southwell points out, as a matter for 

 regret, that the sealers have recently taken to collecting musk- 

 ox hides, which may easily lead to the extermination of that 

 remarkable animal, unless efficient measures be promptly taken 

 for its protection. 



In the March number of Photography, Mr. Douglas English 

 gives the results of his experiments on photographing living 

 fish — an art that has hitherto received but little attention. How 

 necessary is this art, if we wish to have correct portraits of fish, 

 will be apparent when the remarks of the author are read as 

 to the immense alteration which takes place in their bodily 

 form and proportions immediately after death. The difficulties 

 with which the photographer has to contend are the mobility 

 of the fish, which necessitates very short exposures ; the great 

 loss of actinic power in white light resulting from its passage 

 through glass and water ; and, in some instances, the delicacy 

 of the subject and its terror under the operation. In order to 

 counteract the first of these difficulties, Mr. English has adopted 

 the principle of the "animalcule-tank" employed in connection 

 with the optical lantern. After several attempts, a tank was 

 invented capable of confining a living fish within a space suffi- 

 ciently limited to enable the photographer to keep it in some 

 degree in focus, the sides being constructed of two parallel 

 plates of the thinnest and whitest plate-glass procurable, with 

 provision for increasing or narrowing its diameter, within cer- 

 tain limits, according to the size of the fish. Several examples 

 of the photographs thus obtained are reproduced ; and although 

 their definition is not as sharp as might be desired, they are 

 life-like portraits which ought to be of the highest value to the 

 naturalist. 



Mr. Barrett-Hamilton is turning his attention to the cause 

 of the colour-change in animals which turn white in winter. In 

 a recent issue of the Proc. Zool. Soc. he corroborates the view that 

 the darker colour of the summer coat of the Arctic hare is due 

 to the casting off of the white winter hairs and their replace- 

 ment by a new growth. In the January number of the Annals 

 and Magazine of Nat. Hist., Mr. Hamilton discusses the local 

 colour-phases of the Weasel. In the far north, as is well known, 



