628 



NATURE 



[October 29, 1903 



up to the end of 1901, of the well-known earthquake register 

 compiled at the Central Meteorological Office in Rome. 

 The late appearance of this publication arises from the fact 

 that with the Italian records there are incorporated corre- 

 sponding records which have been collected from seismo- 

 logical stations throughout the world. In this publication 

 we therefore have not only entries relating to disturbances 

 confined to the Italian peninsula, but also of practically all 

 the large earthquakes of the world. 



We have received from the Cambridge Scientific Instru- 

 ment Company its new catalogue of Duddell oscillo- 

 graphs. These instruments were described in detail in 

 Nature of December 6, 1900 (vol. Ixiii. p. 142). Since that 

 time several improvements have been made in their con- 

 struction which have the effect of making them more trust- 

 worthy instruments, and better able to withstand the some- 

 what rough usage which they are likely to meet with in 

 engineering work. We note also that a double permanent 

 magnet oscillograph is now on the market ; this instrument 

 has two sets of strips, and is thus able to show the wave- 

 forms of current and P.D. simultaneously; hitherto the 

 portable instrument has only been made with one set of 

 strips. Amongst the illustrations to the catalogue are a 

 number of excellent reproductions of oscillograph records, 

 which serve to show the variety of purposes for which the 

 instrument is suited. One has only to turn to any of the 

 more recent papers dealing with alternate current working 

 to see how important a part the oscillograph is now play- 

 ing and is destined to play in the future in this branch 

 of electrical engineering. 



We have also received from the Cambridge Scientific 

 Instrument Company a pamphlet describing Prof. 

 Callendar's apparatus for measuring the mechanical equiva- 

 lent of heat, which was recently described before the 

 Physical Society, and a second pamphlet relating to the 

 application of electric resistance thermometry to meteor- 

 ology. This latter paper sets forth some of the cases in 

 which the use of resistance thermometers is peculiarly suit- 

 able, as, for example, the measurement of water tempera- 

 tures or underground temperatures. The method can be 

 used with much advantage for measuring or recording 

 temperatures at some distance from the observatory, and 

 has the additional recommendation that the thermometer 

 itself need not be disturbed or approached when the reading 

 is taken. We pointed out some of the other uses of these 

 thermometers in these columns a few weeks ago. 



In a recent number of the Bulletin de la SocUti 

 d' Encouragement pour I'Industrie nationale. M. Charies 

 Henry has an interesting paper on the luminous efficiency 

 of oil lamps and flames generally. He shows that the 

 efficiency increases with the intensity, at first very rapidly, 

 as the intensity rises from i to 2 carcels, and then more 

 slowly, becoming practically constant at 3 carcels. The 

 same has been shown to be true for arc lamps, the law of 

 variation being neariy the same in both cases, only the 

 arc lamp naturally varies over a much wider candle-power 

 range; the efficiency does not become a maximum, in fact, 

 until about 600 carcels. If the efficiencies at their re- 

 spective maxima are compared, the arc lamp is found to be 

 approximately five times as good as an oil lamp, one carcel- 

 second being obtained for an expenditure of 70 watts in 

 the one case and of 320 in the other ; this is allowing for 

 the losses in the boiler, engine and dynamo generating the 

 current, and represents, therefore, the actual superiority 

 of the arc over the oil lamp. If, however, the efficiencies at 

 equal candle-power are compared, the oil lamp is three 

 NO. 1774, VOL. 68] 



times as good as art arc — but, of course, an arc of 3 candle- 

 power is never used in practice. The efficiency of the oil 

 lamp may be improved 25 to 40 per cent, by surrounding 

 the lower portion of the flame with a copper ring to prevent 

 loss of heat by convection. 



In the Field of October 17, Mr. G. Renshaw announces 

 that he has found in the museum of the Royal College of 

 Surgeons a skull of the extinct South African blaauwbok 

 {Hippotragus leucophaeus), which is believed to be the only 

 known specimen in existence. 



The Proceedings of the Royal Irish Academy for May 

 contain an important paper by Dr. G. H. Carpenter on 

 the relationships between the classes of Arthropods. The 

 author considers that group to have been derived from a 

 single stock, and since typical insects, crustaceans, and 

 arachnids possess the same number of segments, the 

 ancestral type must likewise have been definite in this 

 respect. Consequently, millepedes and the like must be 

 aberrant types in which the segmentation has been 

 abnormally increased. Probably the ancestral forms were 

 naupliform {i.e. larval) crustaceans, and not, as commonly 

 believed, well-developed annelid worms. 



The Illustrated London News of last week (October 24) 

 contains a special supplement devoted to the first part of an 

 account, illustrated by reproductions from original photo- 

 graphs, of Major Powell-Cotton's recent hunting expedition 

 in Eastern Equatorial Africa. One of the objects of the ex- 

 pedition was, we believe, to obtain specimens of the okapi, 

 but although the celebrated traveller and big-game hunter 

 has been unsuccessful in this respect, he has succeeded in 

 mapping out an extensive tract of hitherto unexplored 

 country, and has likewise acquired much valuable inform- 

 ation with regard to the natives and the fauna. It was 

 during this expedition that the two fine giraffes now 

 mounted in the Natural History Museum were obtained. 

 Special interest attaches to the traveller's discovery of a 

 spot to which elephants resort when about to die, the habit 

 on the part of these animals of having a " dying ground " 

 being paralleled in the case of the South American guanaco. 

 The cave-dwellers of Mount Elgon appear to have made a 

 more favourable impression on Major Powell-Cotton than 

 they did on their discoverer. Sir Harry Johnston. One of 

 the photographs shows a native stalking hartebeests behind 

 an ass on the head of which has been fixed the scalp and 

 horns of one of these antelopes. The conclusion of the 

 account will appear in this week's issue. 



At Rossitten, in eastern Prussia, large numbers of crows 

 and rooks are caught alive in nets every year during the 

 two migration seasons. The director of the station of the 

 German Ornithological Society at Rossitten proposes to try 

 a curious experiment with these birds. Small metal rings 

 bearing a number and date will be attached to one foot of 

 each of them, after which they will be liberated and per- 

 mitted to proceed upon their own paths of migration. 

 Notices have been sent all over Germany requesting that 

 when any of these birds are shot the foot and the ring 

 attached to it may be returned to the director of the " Vogel- 

 warte " at Rossitten. It is quite possible that some of 

 them may stray even as far as the shores of Great Britain, 

 and if this should happen it is hoped that the director's 

 request may be attended to. An accurate record will be 

 kept at Rossitten of the dates of the liberation of every bird 

 and of the locality whence its foot is returned, and it is 

 expected that some interesting deductions will be made from 

 the information thus obtained. 



