248 



THE POPULAR EDUCATOR. 



RECREATIVE SCIENCE. XXI. 



THE PHENAKISTISCOPE BEALE'S AUTOMATIC FACE THE 

 WHEEL ANIMALCULE. 



HALF a century ago an amusing toy was invented, called the 

 Phenakistiscope, from the Greek <pi>a.Ki(cv, to deceive. It 

 consisted of a number of devices painted round the circum- 

 ference of a disc, each device similar in its general subject, but 

 having a difference of position in some of its details in each 

 successive compartment ; in short, a complete action, as that of 

 a ball running around the interior of a ring, was finished in 

 twelve repeats of the device. 



The method of observing the singular illusion of the phena- 

 kistiscope, until Mr. Rose's kalotrope was invented, was to look 

 upon its reflection in a mirror, through slits or openings in the 

 disc, whilst it was in rapid revolution. This mode of using the 

 disc of course confined its use for the time to one individual ; 

 and notwithstanding repeated attempts by the optician, no 

 movement had been contrived by which the illusion could be 

 shown to an entire audience. 



Since the invention of this interesting toy, various eminent 

 opticians sought earnestly for the means of showing it to a 

 whole company at once, and this with a riew to making it a 

 powerful and interesting aid in 

 the production of effects to be 

 exhibited by the magic lantern. 

 All attempts before the inven- 

 tion of Mr. Rose's kalotrope, 

 failed, either from want of 

 efficiency, or from their being 



too intricate and expensive, or Fig. 1. 



from both of these causes to- 

 gether. 



An apparatus for the magic 

 lantern, constructed by Messrs. 

 Duboscq, answered pretty c 

 fairly, but was very limited in ^^^ 

 its results, and this was quite 

 superseded by the larger and 

 more scientific contrivance in- 

 vented and given to the writer 

 by Mr. Rose, called the Photo- 

 drome (light-runner, or light- 

 course), already alluded to at 

 page 233 of this volume of 

 the POPULAR EDUCATOR. 



A further interest was im- 

 parted to this class of optical 



deceptions by the construction 



of the Zoetrope, or Wheel of 



Life, by which a large family party may be amused by the curious 

 movements of various figures seen through slits in a revolving 

 circular box, in which the slips of paper bearing the devices 

 are placed, and changed at pleasure. The enormous sale of 

 these toys reminds the historian of optical toys that the like 

 success attended the sale of Sir David Brewster's kaleidoscope ; 

 indeed, the popularity of both contrivances brings home to us 

 the truth of Goldsmith's words 



" And still they gazed, and still the wonder grew." 

 And deservedly so, for both have become regular inmates of the 

 toy cupboard. There are, however optical contrivances which 

 take a high position on account of the very ingenious manner in 

 which they are contrived ; and amongst machines that illustrate 

 the various phases of "persistence of vision," none are more 

 interesting than those invented by Mr. John Beale, of Green- 

 wich invented not for any personal advantage, but for the 

 advancement of scientific recreation. 



The first to be described is the " Automatic Picture," in 

 which the face of a charming young lady, waking from an appa- 

 rent lethargy, rolls its eyes, opens and shuts its mouth, and 

 occasionally, for the special delectation of "rude" boys, pops 

 out its tongue, or varies the amusement by grinning " horribly 

 a ghastly smile," very provocative of merriment, and useful, as 

 Dr. Walcot says, for 



" Care to our coffin adds a nail, no doubt ; 

 And every grin, so merry, draws one out." 



In Fig. 1 two standards, A A, carry the shaft, B, which is 



turned by the handle, c. A wheel, D, keyed on to the shaft, B, 

 drives a pinion, E, say in the ratio of two to one ; the pinion 

 carries round a shaft, having fixed on it a slotted disc, F, per- 

 forated with eight radial slots or apertures. When a powerful 

 artificial light, either the oxy-hydrogen, or lime-light, or electric 

 light, is arranged in a box with a condensing lens, so as to 

 throw the point of the cone of rays, or focus of rays, through 

 one of the apertures, and of course, when the slotted disc 

 rotates, eight flashes of light will pass at each revolution, and 

 as the wheel and pinion are two to one, sixteen flashes of light 

 will pass, and illuminate the screen a when the automatic 

 face is shown for each turn of the handle c. 



Let us now suppose that on the screen G the smart hat and 

 feathers, curls, neck, shoulders, and bust of a young lady are 

 depicted, but that, instead of a face being shown, an opening is 

 cut through the screen a of the size of the human face, and 

 that on the circular disc,or card, H (Fig.2), which is carried round 

 by the shaft B, and is behind though close up to the screen G, 

 sixteen faces are so arranged that one of these faces shall be in 

 the right position to register with the hole cut through the 

 screen G at each flash of light, so that the face and the hat, 

 curls, neck, shoulders, bust, make np together one complete 

 picture of the human face divine. It is evident that if the six- 

 teen faces were all painted 

 alike, the resultant picture 

 would, when the discs were 

 revolving and the flashes of 

 brilliant light illuminating the 

 screen 6, be apparently the 

 same as when the apparatus 

 was at rest, i.e., when any one 

 of the sixteen drawings of the 

 faces is flush with the opening 

 cut through the screen G. If, 

 however, the sixteen faces are 

 all painted with different ex- 

 pressions, viz., one of them 

 with the eyes and mouth 

 closed, the next with the eyes 

 and mouth a trifle open, and 

 BO on with each succeeding 

 picture of the series, opening 

 the eyes and mouth more and 

 more, then an appearance of 

 opening the eyes and mouth 

 would be given, but, like all 

 other illusions of this class, a 

 mere repetition of the same 

 effects in fixed order would be 

 produced. Mr. Beale' s auto- 

 matic face apparatus enables the experimentalist to produce a 

 novel and curious spontaneous movement on the part of the 

 "lady," who elegantly diversifies the effects already mentioned 

 by thrusting out her tongue occasionally. 



This part of the illusory effect is thus obtained: 'the sixteen 

 faces form two distinct groups of eight each, as arranged and 

 painted on the card disc. Fig. 2 ; the figures 1 to 8 are faces 

 arranged as already described, showing by a series of gradations 

 the opening and shutting of the eyes and mouth ; and the letters 

 a to h are the other group, snowing eyes always open, but 

 rolling from side to side, and instead of displaying the opening 

 and shutting of the mouth, suppose the tongue to be gradually 

 protruded so as to hang in a neglige style over the chin, it is 

 evident that the operator has two groups of face pictures 

 painted on the same disc, making different motions. 



It must be remembered that the sixteen faces are successively 

 illuminated by flashes of light through the eight slots, or aper- 

 tures, and it will be seen that if every other slot is closed, so as 

 to leave four apertures open, they will illuminate one group of 

 the sixteen faces ; and if those slots are closed in their turn, 

 the other four apertures will illuminate the second group of the 

 sixteen faces. 



To enable the operator to do this, there is placed in front of 

 the slotted disc another disc called the interceptor which in 

 fact constitutes the novelty in the mechanism of the " auto- 

 matic face" so arranged as to allow every other slot to be 

 open, and every other slot to be closed ; and this interceptor is 

 not fixed tightly on the shaft, but is driven merely by friction 



