WATCH. 



ptTOtted into Uie cock G. In the prefent pofition, the 

 finger carried by the fpring-arbor is refting on the plain or 

 iinindented part of piece F, and is keeping the fpring to its 

 required degree of tenfion. When the key for winding is 

 applied to the fquarc of tliis arbor, the teeth of piece F re- 

 gnlate the number of turns that the fpring requires to be 

 wound, before it comes to its due tenfion for driving the 

 warning-train. The wheel n, under the cock H, is on the 

 arbor of the pinion driven, within the frame, by the great 

 wheel, and may be called the fecond wheel of the warning- 

 train ; and the pinion driven by it is on the fame arbor as 

 the efcapement-wheel R, (pivotted alfo into cock H,l which 

 is the third or laft wheel of the train. The teeth of the 

 efcapement-wheel, when put in motion by the main-fpring 

 urging it through the train, afts with the two pallets a 

 and // alternately, which are conneftcd by the portions of 

 two fmall wheels : that reprefented by a is faft to the fquare 

 end of the hammer-arbor, concealed in the frame ; and the 

 other, b, turns on a fixed ftud on the plate. The forked 

 piece or angular lever 12, of the piece b, embraces the 

 angular end d of the warning-detent df^, which is moveable 

 at f, while the remote end 4 preffes on a fpiral plate p, 

 made fail to the wheel of the hours C, by the adtion of the 

 fpring q. Now as plate p revolves once in twelve hours, 

 and has only one ftep at 0, the end of the fpiral, it is ob- 

 vious that, when this ftep comes to the angular point 4 of 

 the detent, this point will drop fuddenly towards the centre 

 of the hours-wheel, and at the fame inftant the angular end d 

 will quit the fork i 2 of the piece b, which will now be at 

 liberty to obey the force of the efcapement-wheel R, exerted 

 on the pallets a and b alternately ; and the concealed femi- 

 circular hammer, on the arbor of pallet a, will ftrike at both 

 ends alternately againft the fonorous ring that produces the 

 warning noife, until the finger of A has gathered up all the 

 teeth of piece F, and is again arrefted on the oppofite point 

 of the diameter beyond the laft tooth. At x the piece b 

 has a tail-piece, which vibrates between the elaftic prongs 

 of the fixed fork P, and thus brings back the hammer after 

 each ftroke to the right and left ; and the frequency and 

 loudnefs of thefe reiterated ftrokes are competent to roufe 

 any perfon, not too lethargic, from a ftate of fteep. A 

 fmall dial-plate lying over the centre of the watch-face, and 

 divided into twelve hours and parts, is fo connefted with 

 the fpiral-plate p, that turning this dial to a pointer, made 

 on the ftiort end of the hour-hand, will put the ftep mto 

 a proper fituation for making the point 4 of the detent fall 

 at the time required, and will confequently produce the 

 alarm at the time for which the fmall dial is thus adjufted. 



Warning Watch by Berrollas. — In the year 1810 we find 

 J. A. Berrollas refiding in Coppice-row, Clcrkenwell, and 

 taking out a patent, on the 26th of May of that year, for 

 a warning watch of a new conftruftion, which we will next 

 proceed to defcribe ; but the defcription given of this in- 

 vention in the Repertory of Arts, &c. is fo imptrfeft, at 

 leaft to us fo unintelligible, that we have been obliged to 

 alter both the drawings and explanation, before we could 

 make the mechanical contrivances undcrftood. The reafons 

 which fcem to have induced Berrollas to attempt a new con- 

 ftruftion of a warning watch, were the inconveniences at- 

 tending winding up, fetting to time, and turning the fmall 

 dial-plate, all which he profefles to have obviated. We 

 have ftiewn the different parts of this mechanifm in feveral 

 figures in Plate XLIV., which we (hall now proceed to 

 explain in our own way. \nfig. lO, a (liews the place of 

 the main-fpring, and b the fiifee of the ordinary works, 

 which are conftrufted in the common way, but which arc 

 sot feen m fg. 11, that reprefcnts an elongated feftion of 



the warning mechanifm and dial-work only. At c i« the 

 arbor of the warning-fpring box, of the great wheel of 

 60 teeth, and of a ratchet-wheel, which is made of ftccl 

 with 33 teeth, that catch the tail of the hammer d, and 

 make it ftrike againft the circular rim of fteel, while the 

 fpring e brings back the hammer after each ftroke. This 

 part of the mechanifm is not given in the original drawings, 

 nor yet Jig. 11, which explains the aftion. As the ftrokes 

 are made by a wheel on the arbor of the fpring-box, it was 

 neceftary that it fhould wind five times round, that the 

 blows might be fufficiently numerous and loud for giving 

 the alarm : hence 165 (33 x 5) ftrokes are given at once 

 winding, and the firft is the loudeft, as being urged by the 

 warning-fpring, without a fufee, at its greateft degree of 

 tenfion ; an advantage which the inventor feems to have 

 overlooked in his own account. Thefe parts, and alfo the 

 pinion f, are planted within the frame, as feen in Jig. 1 1 ; 

 but the parts ftiewn in ^gs. 9, 13, and 14, are on the ex- 

 terior face of the upper-plate, agreeably to the calliper given 

 in Jig. 9, but ading together, as more clearly reprefented 

 in Jig. II, where the pivot-holes are fuppofed to be in a 

 right line, for the fole purpofe of explanation. The arbor 

 ofpinion/ afcends through the upper-plate of the frame, and 

 has the wheel o attached to it, which drives a fecond pinion 

 on the arbor of an efcapement-wheel h ; which two wheels 

 are pivotted above into a long cock, fcrewed to the upper 

 plate ; all which pofitions are clearly feen in fig. I I, as well 

 as the mode by which the motion and force are tranfmitted 

 from the main-fpring c to the pallets »', i. The wheel g \\ia 

 45 teeth, the efcapement-wheel 20, and the two pinions 

 each fix leaves. This aflismblage of wheels and pinions con- 

 ftitutes the warning-train ; but tlie warning detent, on which 

 much ftrefs is laid by the inventor, remains yet to be de- 

 fcribed. This detent i is feen in two detached pofitions, in 

 Jig. 14, where the parts 1,2, and 3, are taken off, to render 

 their ui'es more obvious. The dial-wcrk confifts of a can- 

 non-pinion of 1 2 leaves, the wheel q of 36 teeth on the ftud, 

 its pinion r of 10, and the hours-wheel n of 40, which are 



36 

 common numbers, that may be thus exprefled : viz. — x 



Between the hours-wheel and the 



40 1 440 



10 ~ 120 



cannon-pinion the ring of the detent i furrounds the arbor 

 of the centre-wheel, or rather the tube of the cannon- 

 pinion, but not fo as to be tight upon it : on the hours- 

 wheel n is a pin projedting above and below its plane, as feen 

 in Jg. 1 3, againft which pin the rim of the faid ring is 

 prclfed by the fpring /, as feen in Jig. 9. Now as the 

 fcrcw I takes into the cock 3, made fall to the plate, after 

 it has palTed through a hole in the lever of the detent, this 

 fcrew becomes the centre of motion of the detent, and the 

 prelfure of the fpring / at one end elevates the ring at the 

 other, and with it tlie perpendicular bar /, which reaches to the 

 teeth of the efcapement-wheel /j ; fo that when the elevation 

 of this bar / exceeds the plane of the efcapement-wheel, the 

 train will be at liberty to run on, and the hammer will be 

 made to ftrike a repetition of blows ; but while the elevation 

 of the faid bar / lies in the fame plane with the teeth of the 

 efcapement-wheel, it will operate as a detent to the train, 

 and filence will be prefcrvcd. Above the hours-wheel h, 

 and on its tube, revolves a large additional wheel m, bearing 

 a circular piece of fteel, with an oblong notch cut through 

 it, as feen in Jig. I 3 ; and the pren"ure of the upper end of 

 the pin in the hours-wheel is againft this circular fteel piece 

 at all times, except when it arrives at the faid notch, and 

 then it afcends into it by the downward .irtion 01 the 

 5 C 2 fpriug 



