l« ^ .Weather-Injlrument, Lolian Harp, ^c. 



was carefully attended to through the fummer, particularly when the afpeiSl of the (fcy 

 and ftate of the barorneter feemed to predidt an approaching change ; but the enquiry was 

 fruitlefs, the promlfed found was never heard ; nor did any other circumftance worthy 

 notice occur, except that fome of the fmalleft wires fnapped occafionally in the cold nights 

 of the fpring. The failure of this experiment feems to confirm the fuppofition that M. 

 Lazowflci's inftrument is at bed but an imperfeft Hygrometerjand that it does notpromife 

 any new difcovery relative to the properties or compofition of the atmofphere *. J. G. 



IV. 



Obfervathns on Scylla and Charyldh t- By the Jbbi LazZARO SfALLANZANI, Profejfor of 

 Natural Hijiory at Pavid, F.R.S. i^c. ^c. 



Q 



KjCY'LLK and Charybdis, according to the fables of the poets, are two fea monfters 

 vvhofe dreadful jaws are continually diftended to fwallow unhappy mariners ; the one 

 fituated on the right, and the other on the left extremity of the Strait of Meflina, where 

 Sicily fronts Italy. 



Dextrum Scylla latus, Ixvum Implacata Charybdis 

 Obfidet : atque imo barathri ter gurgite vaflos 



* The paffage in Dr. Huttou's Diftionary will admit of the fenfe, that the obferver (who perhaps nevsr 

 took notice of his wire, except, when bufied in the arnufement there mentioned) did not hear any Ipontancous 

 found, but merely perceived a mufical vibration at certain times during the aft of drawing the mark along 

 the wire, which mud have agitated it. This might arife frointenfion, by fome hygromctric change in the 

 fuuation of the points of fupport. It may be remarked, that a wire for the ufe the clsrg^yuian applied it to 

 muft have been much longer than fix feet; and that it was probably lefs ftretched than the wires expoftd by 

 my correfpondent. 



If the founds were fpontaneous, the faft wjllbe referable to the Eolian harp of Merfennus, fioce re-jnvcntad 

 by Ofwald. The inftrument confifts of a founding board about two fe(;t or more in length, upon which ten 

 or twelve (calgut) firings of equal length but different thicknefs are tuned in unifon, at as low a pitch as the 

 fmalleft of the ftrings can bear. When this is placed in a current of air, fuch for example as palTes through « 

 w indow partly opened, it emits a variety of contemporaneous and fuccelfive tones, which from their thannes 

 in melody, harmony, and fwell, and a certain wild ftraiigenefs in the whole effeft, rivet tlie attention, and 

 fometimes afford exqulfue pleafure. The Eolian harp has been celebrated by Thomfon and other poets. I 

 have not made experiments to analyfe its nK)de of operation ;' but am dilpofed to think, ( i ) that it can only- 

 give the trumpet notes ; (i) that the note to be afforded by any one ftring depends on tlie quantity of the 

 impulfe of the wind being greateft near one end of that ftring; (3) that the fame quantity and direftion of 

 • impulfe will agitate a longer portion of the flack fmall ftring than of the tenfer thick firing, fo that in the 

 vibratory fubdivifions the imallcr ftring will give the graver tone; (4) that a powerful tone drawn ft-om one 

 ftring may difpofc the other ftrings to vibrate unifons, fifths, thirds, oftav'es, and other concords, more or lefs. 

 remote according to the circumftances. 



If M. Lazowfki's wire aaod upon the principle of the Eoliao harp, it might beprefMnKd that xh& recuJrenw 

 %% well »s the nature of the found emitted would be governed by the fores and angle of direftioa of the wind ; 

 and, if fo, much would depend on the expofur^ the direftion and the tenfion of the wir,e. Whether on this 

 fuppofition it could afford any more certain indication of approaching change of weather, than is tfually ob- 

 tained from a finiplc obfervation by the wind vane, muft be decided by fafts, if fuch flioultl hereafter appear. N. 



t Travels in the Two Sicilici. ^nglilh Traofl. IV. 168. 



i Sorbet 



