146 



NATURE 



{Dec. 19, 1878 



The remarkable fact displayed in his portion of the above 

 table, that locusts only make their appearance in great numbers 

 an the interval from minimum to maximum sun-spot and never 

 ducitij the interval from maximum to minimum sun-spot, is 

 evidently regarded by Dr. Plahn as affording some additional 

 collateral proof in favour of the relation he had already par- 

 tially established between the rainfalls of Central Europe and 

 the sun-spots, viz., that the interval from minimum to maximum 

 sun-spot is in general drier and warmer than that from maximum 

 tojninimum sun-spot. The added dates apparently exhibit a 

 relation to the sun-spot epochs similar to those given by Dr. 

 Hahn. 



Whether the laws which rejfulate the visitations of locusts are 

 the same in other parts of the world or not, it is at all events 

 suggestive to notice that the dates of their general appearance 

 throughout the world, given by Mr. Walford in a recent paper 

 to the Statistical Society, entitled, " Famines of the World, 

 Past and Present," exhibit the same relation to the sun-spots as 

 that noted by Dr. Hahn in the case of their visits to Europe. 



The date of apparition, the locality visited, and the epoch of 

 sun-spot minimum corresponding, are given below. 



Epoch of Minimum 



Sun-Spot. 

 ... 1798-3 



... i8io-6 



- 18339 



... 1856-0 



... 18672 



... i877(?) 



... i877(?) 



In the face of such an apparent predilection on the part of 

 locusts to swarm during the minimum epoch of sun-spots, it 

 might, I think, be advantageous to institute an extensive com- 

 parison of all past visitations of these insects with the eleven- 

 year cycle of sun-spots. This after due allowance had been 

 made for any known natural cycles of incubation, might pos- 

 sibly bring to light a physical cycle of visitation, the sizeani 

 position of the area affected by which would, perhaps, afford 

 some indication 01 the corresponding limits of the rainfall 

 variation. E. D. Archibald 



II, Granby Terrace, Glasgow 



The Range of the Mammoth 



T"he criticism by Mr. Clement Reid of my paper recently 

 read before the Geological Society, and not yet published, 

 readers it necessary to remind him that his views as to the 

 mammoth not being pre-glacial are not new, but were advanced 

 by me ten years ago {_Pop. Science Revieiv, 1868, p. 275 ; Geol. 

 Mag., V. 7, July, 1868), and afterwards given up by the light of a 

 wider experience. His arrangement of the complicated glacial 

 deposits of Britain in one linear series, like all similar attempts, 

 appears to me to be based on the fallacy that a difference in the 

 character of the strata, in different areas, implies a difference in 

 point of time. His divisions seem to me purely local, and mostly 

 peculiar to the eastern counties. I see no reason for believing 

 that, while five out of the six proposed were being accumulated 

 (Cast of the Pennine chain, there were no glacial phenomena in 

 the west, in Lancashire or Cheshire, until the last phase, or the 

 sixth of the eastern divisions ; or, in other words, that the lower 

 boulder clay of Lancashire and Cheshire is the equivalent of 

 the last division. On the contrary, the marine sands and gravels 

 covering the lower boulder clays, on both sides of the Pennine 

 chain, and occupying a large area round Crewe, Stafford, and in 

 the Trent Valley, is to me a well-marked horizon, defining the 

 upper from the lower series of boulder clays. It is very Jlikely 

 that the lower boulder clay of Lancashire and Cheshire is the 

 equivalent of the lower boulder clay series of Norfolk and Suf- 

 folk, as well as of the "moraine profonde" of Scotland. It 

 must, however, be admitted that the correlation of the glacial 

 deposits in various parts of Britain has not yet been satisfactorily 

 made out " Tot homines quot sententicC. " 



To group them, as they are frequently now grouped, in one 

 lioear series, seems to me almost as useless as to construct a 

 Imtory of Europe in which the dynasties ruling various kingdoms 

 cat the same time are described one after another, and taken to 

 belong to different periods because they were different dynasties. 



W. Boyd Dawkins 



Fossil Floras of the Arctic Regions 



The author of the valuable paper communicated in Nature, 

 vol xix. p. 124, on " The Fossil Floras of the Arctic Regions," 

 will find in an essay of mine, entitled " Thalassa," and pub- 

 lished in the course of last year, a number of facts and argu- 

 ments in corroboration of his views regarding the influence of 

 oceanic currents upon climate. In this essay, which is mainly 

 founded upon the observations made on board H.M.S. Chal- 

 lenger, I have endeavoured to show how a relatively trifling 

 elevation or depression of the sea-coast or of the bed of 

 the ocean may considerably alter the configuration of an 

 oceanic basin ; how such an alteration must affect the direction, 

 volume and temperature of existing currents, and thus have a 

 tendency to change the climate and ultimately the distribution of 

 animal and plant life in the regions bordering on the oceanic 

 basin. I also (p. 29-30) ventured to express the opinion that 

 "it appears hardly necessary to go in search of vast cosmic 

 changes, such as an alteration in the position of the terrestrial 

 axis, a diminution in the amount of solar heat .... while we 

 have, close at hand, an agency whose effect upon climatic condi- 

 tions may be said to be a matter of daily experience, and which 

 is sufficiently powerful to establish, in almost any region on the 

 earth's surface, the small difference of temperature which is a 

 decree of life or of death to numerous animal and vegetable 

 organism^." To this I may now add, that the influence of 

 oceanic currents upon climate and upon the distribution of life 

 will be most felt and produce the most remarkable results in the 

 Arctic and sub- Arctic regions, which, as we know, may at one 

 period be swept by powerful polar currents, at another invaded 

 by vast masses of warm water brought there by currents from 

 the tropical regions, such, for example, as the Gulf Stream. 



The facts brought to light by recent sounding-operations 

 regarding the configuration of the sea-bottom and the distribution 

 of oceanic depths has led me to the conclusion that our continents 

 and oceanic basins, such as they appear at the present day, 

 are of immense antiquity ; that changes in the distribution of 

 land and water require for their accomplishment long periods, 

 which, for all we know, may alternate with periods of repose or 

 even of retrocession ; and that, consequently, the influence of 

 these changes upon currents and upon climate must be equally 

 slow and uncertain in its duration. If, therefore, the effect ot 

 oceanic currents upon climate appears as an important factor, 

 which can no longer be neglected in any discussion on the flora 

 and fauna of past geological epochs, on the other hand, the slow 

 and uncertain progress of the changes above mentioned seems to 

 afford ample scope for the operation of other causes which, 

 besides climate and temperature, determine the existence of cer- 

 tain species in a given area of the earth's surface. 



J. J. Wild 



The Microphone". 



Two subjects of interest in connection with the practical 

 application of the microphone have lately been brought to my 

 notice by Raja Sir T. Madava Row, K.C.S.I., Dewan of 

 Baroda. In the hope of securing a little assistance from some 

 of your scientific readers I hasten to lay them before you. 



The first question is with reference to the use of a microphone 

 as a stethoscope. It seems that native ladies of high position 

 decline altogether to allow a doctor to examine the chest in the 

 ordinary manner. Sooner than submit to such an examination 

 they would prefer to die — certainly rather a staggering fact for 

 those imbued with European ideas. In the cause of humanity it 

 is therefore desirable to do something for those whose position 

 and t:aste would be imperilled by direct examination. If the 

 microphone could be so delicately arranged as to transmit the 

 auscultatory sounds, a medical ear, even at a distance, would 

 surely be able to detect the existence of any disease of the heart 

 or lungs. In the few experiments that we have made with cm- 

 limited appliances we have been able to hear the ticking of a 

 watch at a distance of about 200 yards, and the roar of a black 

 ant when attacked by his companion, but as yet we have heard 

 no internal sounds from the human breast. Perhaps with better 

 devised instruments some one may have been able to obtain that 

 which has yet been denied to us. I am sure many native ladies 

 would be glad to get an affirmative answer to the question, " Can 

 the microphone be used as a stethoscope ? " 



The second subject seems to me to be a much more difficult 

 one to grapple with. Sir Madava Row writes to me as 

 follows : — 



