488 



NATURE 



[Sept. 5, 1878 



The soiiree of heat must therefore have been in the nest itself. 

 In bees-hives the temperature rises sometimes as high as 38° C. 

 (/^j^ Newport, as cited in Girdwoyn, "Anat. et Physiol, de 

 rAWille," p. 23). We may be allowed to suppose that something 

 ^imjlar happens occasionally also in wasps' nests. Such a heat 

 jni^t be caused by ah alteration beginning in the wax, hydro- 

 carbQn$, .being formed, which, on being absorbed by the paper- 

 like, porous substance of the cell-walls, must get still more 

 h^attfd, so that a comparatively small access of oxygen would be 

 sufBcient to set the whole nest on fire. 



■ ■ I have been assured that the spontaneous combustion of 

 wasps' nests is a well-known fact in the interior of Venezuela, 

 and as I do not recollect having found it mentioned in books, 

 itj appeared to me worth while to inquire whether something 

 similar has been observed in other parts of the world, and if 

 so, whether my explanation will hold good in all cases. 

 ".Oaracas, July 15 A. Ernjst 



Observations on a " Dust-Whirl " 



While making magnetic determinations at Kirksville, Mo., 

 several "dust- whirls," or small whirlwinds, were observed, 

 which, although not destructive in their effects, were unusually 

 violent. The dust was carried by strong surface-winds, which 

 rushed inward to the centre of the whirl, rising in a vast column 

 200 feet high. 



. One of these whirls crossed a pond of water, moving very 

 slowly, and in a zigz,n.g path. The \vater immediately became 

 agitated, a depression was formed, which extended to the bottom 

 of the pond (which was about five feet in depth). The top of 

 the cup-shaped depression was about six feet in diameter, the 

 bottom about four or five feet. There was no water drawn up 

 from the pond, so far as could be observed, although a little of 

 the rapidly .whirling water at the edge of the depression was 

 thrown outwards upon the surface of the pond, 



Kirksville is situated in the northern part of the State of 

 Missouri, and on the summit of the divide between the Missis- 

 sippi and Missouri Rivers. During the present summer it has 

 had the least rain in the State, and is yet parched by excessive 

 drought. Francis E. Nipher 



August 5 



The Telephone 



On to the centre of a telephone vibrating disc, and perpen- 

 dicular to its plane, a light needle \ inch long was soldered, the 

 disc held in a holder, mouth-piece, &c., the same as a telephone, 

 and so arranged that the needle would vibrate in a small cylin- 

 drical ebonite cup, \ inch in diameter find J inch long, the top 

 of the ebonite cup just free from touching the vibrating disc ; a 

 copper wire was let into the centime of the bottom of the cylinder, 

 flush with the bottom ; the cylinder was filled full with the finest 

 dust of iron filings well shaken down.^ , A battery circuit was 

 then completed with connecting wires, through the vibrating 

 disc, iron filings, the copper wire let into the bottom of the 

 cylinder, and through a pair of telephones in a distant room ; 

 after finding out by experiment the distance off the speaker 

 ought to stand when speaking to this transmitter, and the proper 

 degree of loudness he ought to give to his words, the voice came 

 as clearly (and louder) as if a telephone had been used for a 

 transmitter. If the speaker came too close or spoke too loudly 

 the words were indistinct, and mixed up with a fizzing sound. 

 In the experiment which was most successful the speaker was 

 about 1 8 inches from the transmitter and spoke in an ordinary 

 tone of voice. But this distance I found to vary with the thick- 

 ness of the vibrating disc ; a thin disc transmitted clearly only 

 when the speaker was 3 feet off. 



The ebonite cylinder was also filled with water (distilled) as 

 an experiment, instead of iron filings. I thought that possibly the 

 resistance of the circuit would be altered through the water, as 

 the needle vibrated to and from the copper wire opposite to it ; 

 but no sounds were found to be transmitted. If the resistance 

 of the circuit was altered when the disc vibrated in this experi- 

 ment, it might tend to support the idea that alteration in the 

 resistance of a circuit was not the only thing required to cause 

 sound to be transmitted, but that "false contact" was necessary, 

 such as would take place when the needle vibrated in the iron 

 filings. G. R. R. Savage 



Roorkee, July 8 



The disc well tapped with the hand so as to loosen the filings round the 

 needle. 



The Electro-Magnet a Receiving Telephone 



The result I have arrived at whilst experimenting in this 

 direction seems so interesting, and at the same time, I believe, 

 novel, viz. , that a good receiving telephone can be made from electro- 

 magnets alone without any vibrating diaphragm, that I hope by 

 prior publication, to prevent the possibility of a string of those 

 patents which nowadays so greatly hamper true scientific inven- 

 tion. 



In my earlier experiments I made an electro -magnet out of a 

 piece off-inch iron gas pipe | inch long, filed flat on one side, and 

 split sufficiently only to allow the wire (No. 24) to be wound on, 

 which was done till it was full inside. The poles were therefore 

 together about \ inch square. This was fixed inside a small 

 cigar box, under a ferrotype plate, covering a rectangular hole 

 cut in the lid 2\ inch by \\ inch. With a Hughes' carbon- 

 pencil-microphone tilted to an angle of 45° as a traasmitter, a 

 small musical box as a source of sound, in a distant part of the 

 house, and one of Leclanche's cells in circuit, this box gave 

 out tunes plainly heard by all sitting in the room. 



Whilst experimenting with another similar magnet, I stood it 

 loose, poles downwards, but still connected with the line wires 

 on a flat tin gunpowder canister with the ends cut off, but still 

 retaining the paper label on which the magnet lay ; the tune 

 of the musical box was given out loudly and resonant, but 

 buzzing and jangling ; also words spoken to the transmitter were 

 heard, but confused together. 



Now this was a very interesting result, which led to the next 

 discovery ; for, having a small ordinary electro -magnet with its 

 armature in front (as used in electric bells), fixed to a piece of 

 board, I was about to unship it to try experiments in various tin 

 cans, &c., when it occurred to me to connect it as it was, to the 

 line wires, placing only a slip of paper between the poles and 

 armature to prevent actual contact. To my astonishment, on 

 putting the ear close to the board at any part, the music of the 

 box was heard clearly, every note from highest to lowest being 

 distinctly given. Now here seemed to be a telephone without a 

 vibrating diaphragm ; but, to make more sure, the armaturewas un- 

 screwed from its support and attached to the magnet only by an 

 india-rubber band, with the slip of paper between it and the 

 poles, so that it touched no other part of the apparatus. On 

 listening to the supporting board, the sounds were heard as 

 distinctly as before. 



But even here forensic ingenuity might claim and attempt to 

 prove that this ordinary armature was a vibrating diaphragm ; 

 therefore, an armature being itself nothing but an induced 

 magnet, it was replaced by another electro -magnet, thus : — 



Two ordinary electro-magnets (unscrewed from a couple of 

 large electric bells) were fastened, by means of two little wooden 

 saddles and a screw each, to a small piece of deal board about 

 45 inches square and f inch thick, in such a way that the poles 

 were all but touching. Their wires were then j oined so that poles of 

 opposite denominations faced each other, i.e., north opposite south 

 and vice versd. This placed on an empty cigar-box and four 

 Leclanche cells in circuit, gave out the tune of the musical box 

 clearly and loudly in the room. When both poles were made 

 to touch, the sound ceased ; but with a thin piece of paper 

 or stout tin-foil between them, without any intervening air space, 

 the sound was heard. On gradually separating the magnets, 

 the sounds grew fainter and fainter, till they became inaudible. 



By putting the base-board close to the ear, whistUng and 

 singing to the microphone were very clearly and loudly heard, also 

 the voice of the person speaking could be recognised ; but words 

 were hardly sufficiently defined to distinguish all that was said, 

 though now and then parts were intelligible. 



One of the electro-magnets was afterwards replaced by a small 

 permanent steel horse-shoe magnet fastened to the board in a 

 similar manner, the resvilt was the same, but, I imagined, slightly 

 louder, probably from there being less resistance. 



By varying the strength of battery, size, or mode of mounting 

 magnets, or adjustment of the microphone, I have no doubt that 

 perfect definition can be obtained. The loudness and volume of 

 the sound are ample ; but before making further experiments, 

 for which I have at present little time, I hasten to communicate 

 theyac/ that the electro -magnet, without any diaphragm whatever, 

 can be made a reproducer of sounds transmitted by a Hughes' 

 microphone, and thus a complete and practical telephone system 

 produced without the possibility of infringing anybody's Mtent. 



I must add that the same arrangement is also a feeble trans- 

 mitter, using a good Bell's telephone as a receiver, which is a 

 very strange fact. I abstain at present from all theory on the 

 subject. F- G. Lloyd 



