48 



NATURE 



\_Nov. 15, 1877 



Bournemouth a small bed of dark clay was found full of 

 leaves of feather palm, crossing each other in every direc- 

 tion ; the tip of a frond in my collection measures four 

 feet in length, by three feet broad. Amongst other 

 interesting specimens is a Smilax leaf of larger dimensions 

 than any now living, and a twig of Dryandra, with many 

 leaves attached, from Alum Bay, which unites in itself 

 several of M, Watelet's species from the Gr^s du 

 Soissonnais. The discovery of a finely preserved neurop- 

 terous wing, and of two apparently hemipterous abdomens, 

 are of interest in connection with the large series of insect 

 remains from Gurnet Bay, Isle of Wight, lately deposited 

 in the British Museum. 



The history remains to be written| of the subsidence of 

 the great continent, whose further limits Edward Forbes 

 surmised are yet traceable in the banks of Gulf Weed, 

 ranging between the 15th and 45th parallels. Many, 

 howevei", have written on Atlantis, but lacking the direct 

 proof of its former existence in comparatively recent 

 times, which has since come to light. The disappearance 

 of almost an entire continent, is not a more startling 

 proposition than the elevation of the Alps, Pyrenees, 

 Apennines, and Carpathians, over whose highest summits 

 the sea rolled at this period. Of the history of this dis- 

 appearance Bournemouth presents us with but a page, 

 still a page full of meaning. The incoming and disap- 

 pearance in succession of oaks and beeches, figs and 

 laurels, palms and delicate ferns, the swamp-loving aroids 

 and Eucalyptus, Chrysodeum and Osmunda, on the same 

 spot ; the appearance in masses of the fruit of Nipa, 

 which is stated by travellers to be found in brackish 

 estuaries ; the incoming of shore crabs and mud-boring 

 Crustacea, sea-shells and Flustra, shingle beeches and 

 deeper sea deposits, are each well-marked stages in the 

 history of the disappearance of this continent, whose 

 existence at this and a later period may be gathered from 

 the writings, made from diff"erent standpoints, of Prestwich, 

 Godwin-Austen, Sorby, and many others. The Bourne- 

 mouth and Sheppey vegetable [remains were brought 

 down by one of the rivers draining this continent, which 

 at a later period silted over the reptiles of Hordwell and 

 the estuarine shells of the fluvio-marine series. That the 

 oscillations which gradually led to the disappearance of 

 the land, vestiges of which remain in Cornwall, the 

 Channel Isles, Brittany, Madeira, &c., have not ceased, 

 even in historic times, there is ample local evidence to 

 show. This branch of the subject, however, is scarcely 

 yet ripe for discussion, nor would space here allow it to be 

 fully entered into. 



Baron Ettingshausen and myself are preparing a 

 monograph upon the ferns of this flora which I hope very 

 shortly to place in the hands of the Palasontographical 

 Society. J. s. Gardner 



THE TELEPHONE 

 A T the Society of Telegraph Engineers on the evening 

 -^-*- of October 31 a lecture of great interest was given 

 by Prof. Graham Bell on the Telephone, with the inven- 

 tion and improvement of which his name is so intimately 

 connected. The lecture was largely illustrated by dia- 

 grams, to which Prof. Bell: made constant reference, and 

 with these illustrations will be published at length in the 

 forthcoming part of the Journal of the Society. We 

 have already given a full account of the telephone and its 

 prmciples, and will only now refer to some of the 

 mteresting episodes which occurred in the course of Prof. 

 Bell's experiments. 



Prof. Bell's account of his experiments for devising 

 methods of exhibiting the vibrations of sound, specially 

 ^r use m teaching the deaf and dumb, is very interesting. 

 For some time he carried on experiments with the mano- 

 metnc capsule of Koenig, and with the phonautograph of 

 Ldon Scott He was led to the idea of constructing a 



phonautograph modelled closely on the mechanism of the 

 human ear, and at the suggestion of Dr. C. J. Blake, he 

 made use of the human ear itself, a specimen of which 

 was prepared by Dr. Blake, for conducting these experi- 

 ments. 



It occurred to him that if a membrane as thin as tissue 

 paper could control the vibration of bones that were, 

 compared to it, of immense size and weight, why should 

 not a larger and thicker membrane be able to vibrate a 

 piece of iron in front of an electro-magnet, in which case 

 the complication of steel rods in his first form of telephone 

 could be done away with, and a simple piece of iron 

 attached to a membrane be placed at either end of the 

 telegraphic circuit. 



The form of apparatus he was then employing for pro- 

 ducing undulatory currents of electricity for the purposes 

 of multiple telegraphy he describes thus : a steel reed was 

 clamped firmly by one extremity to the uncovered leg of 

 an electro-magnet, and the free end of the reed projected 

 above the covered leg. When the reed was vibrated in 

 any mechanical way, the battery current was thrown into 

 waves, and electrical undulations traversed the circuit, 

 throwing into vibration the corresponding reed at the 

 other end of circuit. He immediately proceeded to put 

 his new idea to the test of practical experiment, and for 

 this purpose he attached the reed loosely by one extremity 

 to the uncovered pole of the magnet, and fastened the 

 other extremity to the centre of a stretched membrane of 

 goldbeater's skin. He presumed that upon speaking in 

 the neighbourhood of the membrane it would be thrown 

 into vibration and cause the steel reed to move in a 

 similar manner, occasioning undulations in the electrical 

 current that would correspond to the changes in the density 

 of the air during production of the sound ; and he further 

 thought that the change of the intensity of the current at 

 the receiving end would cause the magnet there to attract 

 the reed at that end in such a manner that it should copy 

 the motion of the reed at the transmitting end, in which 

 case its movements would occasion a sound from the 

 membrane there similar in timbre to that which had 

 occasioned the original vibration. 



The results, however, were unsatisfactory and discour- 

 aging. With a reduction, however, in the size and weight 

 of the spring employed, distinctly audible effects were 

 obtained. " I remember," Prof. Bell said, " an experi- 

 ment made with this telephone, which at the time gave 

 me great satisfaction and delight. One of the telephones 

 was placed in my lecture-room in the Boston University, 

 and the other in the basement of the adjoining building. 

 One of my students repaired to the distant telephone to 

 observe the effects of articulate speech, while I uttered the 

 sentence, 'Do you understand what I say?' into the 

 telephone placed in the lecture-hall. To my delight an 

 answer was returned through the instrument itself, articu- 

 late sounds proceeded from the steel spring attached to 

 the steel membrane, and I heard the sentence, * Yes, I 

 understand you perfectly.' It is a mistake, however, to 

 suppose that the articulation was by any means perfect, 

 and expectancy no doubt had a great deal to do with my 

 recognition of the sentence ; still, the articulation was 

 there, and I recognised the fact that the indistinctness was 

 entirely due to the imperfection of the instrument." After 

 a time he produced a form of instrument which served 

 very well as a receiving telephone ; and it was in this 

 condition his invention was exhibited at the Centennial 

 Exhibition in Philadelphia. It was in this condition also 

 that Sir William Thomson exhibited the instrument to 

 the British Association in Glasgow. 



In pursuing his investigations Prof. Bell has come across 

 many interesting facts which we regret we cannot refer to 

 in detail. It has long been known that when an inter- 

 mittent current of electricity is passed through the coils 

 of an electro-magnet a musical tone proceeds from the 

 magnet. " I have discovered," he said, " that these sounds 



