3o8 



NA TURE 



\_Feb. 14, 1878 



At Monach, on November 15, at 12.43 P-'^-j the baro- 

 meter was 29703 ; 9 P.M., 29*05 1 ; 11 P.M., 28807 inches ; 

 after which it began to rise, and at 9 A.M. of the following 

 morning it had risen to 29'828 inches, a fluctuation of 

 nearly two inches having taken place during the twenty 

 hours ending 9 A.M. of the 16th. The storm accom- 

 panying this depression of tiie barometer rose at 10.30 P.M., 

 about the time of lowest pressure to the force of a true 

 hurricane, the worst the observer had ever seen during 

 his twenty years' service as a lightkeeper. At the same 

 dates, at Thorshavn, Faro, the readings of the barometer 

 were — lowest at midnight of the nth, 281x9 inches; 

 15th, at 9 A.M., 29*002 inches, and at 9 P.M., 29350 

 inches, the barometer thus rising a third of an inch in 

 Faro during the time that it fell about an inch in the 

 outer Hebrides, accompanied by a storm of extra- 

 ordinary violence, being the heaviest storm experienced 

 in the north-west of Scotland generally for very many 

 years. 



Cumulative Temperatures. — To simplify the dif- 

 ficulty of obtaining sums of temperature (a highly 

 important climatological factor, particularly in its appli- 

 cation to agriculture) for any district, from the ordinary 

 instruments, M. von Sterneck has recently proposed to 

 obtain these indirectly by observation of the sums of 

 actions produced by the temperature. A suitable appa- 

 ratus for this we have in the pendulum-clock. The course 

 of this represents the sums of the heat-changes, since it 

 represents the sum of the changes of length of the 

 pendulum, produced by different temperatures, which 

 changes cause variations in the time of oscillation. As 

 the laws of pendulum vibrations and the expansion of 

 substances through heat are known, the true sums of tem- 

 perature can be deduced from the going of the clock. 

 While the watch-maker is concerned to obtain as uniform 

 working as possible, and uses arrangements to compen- 

 sate the changes in length of the pendulum, the present 

 case requires that these changes should be brought into 

 prominence ; so the pendulum is made of some substance 

 (like zinc) which expands greatly through heat. The 

 clock will reveal the variations of temperature by its 

 slowness or fastness, and by comparing its indications, at 

 certain times, with those of a uniformly-going clock, the 

 sum of divergences of the temperature from any given 

 temperature will be ascertained. The principle of this 

 method can also be applied (as the author shows) to 

 determine the variations in atmospheric pressure and in 

 the intensity of magnetism. 



GEOGRAPHICAL NOTES 

 Brazil.— Mr. Herbert H. Smith has returned to Balti- 

 more, U.S., after an absence of several years employed 

 in scientific explorations in Brazil. Leaving the United 

 States in January, 1874, for Pard, he ascended the Ama- 

 zon to Santarem, where he was engaged for two years in 

 collecting and studying the insect fauna of that region. 

 Subsequently he extended his explorations to the north 

 side of the Amazon and on the tributary rivers, as far as 

 the base of the great northern table-land. A collection 

 of insects made by him during this period amounted to 

 12,000 species, with 100,000 specimens, accompanied by 

 copious notes on the habits, geographical distribution, &c. 

 During 1876 and the early part of 1877 he was connected 

 with the Brazilian Geological Commission in exanriining 

 the geological structure of the country. He succeeded in 

 making a section of the Devonian rocks of the Amazon 

 region, and discovered a rich carboniferous bed on the 

 north side of the Amazon, in the vicinity of Alenguer. 

 The results of this labour are in the course of publication 

 by Prof. Harrt, of the Geological Survey. Several months 

 of his absence were spent in the southern part of Brazil, 

 near Rio de Janeiro and Minas. Mr. Smith has been 

 able to make some interesting inferences in regard to the 

 geological distribution of Brazilian animals. Bates and 



Wallace have pointed out that the Amazon forms a limit 

 to the migration of many animals. Mr. Smith is of the 

 opinion that the flood plains of the valley, which average 

 forty miles in width, constitute a far more effectual barrier 

 than a body of water of the same breadth. Birds and 

 insects of powerful flight pass this distance without diffi- 

 culty, and are generally found on both sides ; but the 

 sluggish species, especially the wingless forms, like 

 spiders, are generally confined to one side or the other. 

 This is especially shown in those hymenopterous species 

 in which the females are wingless, as the mutillarias, 

 pezomactri, &c. Here the distinction between the north- 

 ern and southern groups is very striking. The broad 

 alluvial belt through which the Amazon flows constitutes 

 a very distinct zoological province, in which many of the 

 forms appear to have been derived from those of the high 

 land. The contributions of Mr. Smith to geographical 

 knowledge have not been inconsiderable. His maps of 

 the physical geography of the Lower Amazon and of 

 three important tributaries, the Curna, the Msecuru, and 

 the Jaurucu, are especially noteworthy. The last-men- 

 tioned has been entirely lost sight of by modern geogra- 

 phers, though referred to by earlier travellers. This enters 

 the delta of the Xingu close to the Amazon, and is 

 apparently navigable for steamers to a distance of 150 

 miles from its mouth. Mr. Smith returns to the United 

 States for the purpose of making arrangements for con- 

 tinuing his explorations for several years longer, so as to 

 accumulate a sufficient body of facts to work out satis- 

 factorily the entire problem of the derivation and the 

 geographical distribution of the insects of Brazil. 



Africa. — Herr Schiitt, who has been despatched by 

 the Deutsche afrikinische Gesellschaft to equatorial 

 Africa, has safely arrived in San Paul de Loando, and 

 starts at once for the interior to complete the work of 

 exploration commenced by Eduard Mohr, whose un- 

 timely fate we lately recorded. The series of geographical 

 lectures in Berlin, delivered under the auspices of the 

 Afrikanische Gesellschaft, was opened on January 23, by 

 Dr. Nachtigal, who gave a graphic description of the 

 African ^kingdom Darfur, which was conquered in 1874 

 by the Egyptians. 



Arctic Exploration. — We learn from L Exploraieur 

 that Mr. Gordon Bennett, of the New York Herald, 

 intends to equip an expedition for polar exploration. 



The Angara.— At its last meeting, February 5, the 

 Section of Physical Geography of the Russian Geogra- 

 phical Society discussed the question of the expedition 

 to be sent for the exploration of the Angara and of the 

 water-divide between the Obi and Yenisei rivers, where, 

 it is expected, a water communication could be established 

 between the two main rivers of Siberia, An elaborate 

 report was read, being a sketch of the present state of 

 our knowledge of these tracts, and of the recent explora- 

 tions of the water-divide ; the route the expedition will 

 have to follow was also discussed. 



An Az[muth Instrument. — Capt. Mouchez has pre- 

 sented to the Geographical Society of Paris a portable 

 instrument for taking azimuths and altitudes in travelling. 

 The weight is only a few pounds, and the experiments 

 made at Montsouris show that the latitude can be taken 

 with an error of a i&^ minutes. This instrument is to be 

 used by some travellers that the Paris Geographical Society 

 is sending out to Africa. A single man can carry the 

 apparatus and use it without losing much time. A com- 

 plete observation requires less than a quarter of an hour. 



NOTES 

 At the meeting of the Linnean Society on Thursday last, it 

 was unanimously resolved to send a congratulatory letter to von 

 Siebold on the occasion of his jubilee. This graceful act, how- 

 ever, bruigs into prominence the neglect of the Society to take 



