THE MECHANISM OF O’SHAUGHNESSY’S MODEL. 
43 ^ 
wlih tlie masnets*, ihe vvlieel started off, and from 
Ihe first moveiiieni woikrd ilie polf-chaiigei wiili 
ease. Ihe velocity wiih whicli it revolved was 
very considerable - namely, lO revoliiiioiis in a 
iiiiiiiite ; ainl this velocity was perfectly iiniioim as 
loiii! as the galvanic excitement was sustained. 
1 he' force was so great that the support of the ex- 
tetnal magnet was repeatedly diagged inwaids to 
the wheel, and the magnets came in contact with a 
stroke that made the fiame vibiate, to oliviate this 
we were obliged to tit iti another very sir -tig sup- 
port. 
Seveial experiments were subseqitetilly made 
with Ibis model, as well to deieiiiiine its actn I 
woikitig power, as to obtain tl,ie n<-ressary data 
for the construction of a larger macbine. 
A corti was aiiathed to the axle, made to iilav 
over a pnlle} hall an inch in diumeier, and con- 
nected with a scale. on starting the model, ihe 
axlelified 10 'toy ounces while the wheel wus re- 
volving forty limes, and a tiov i>onnd while ie- 
volving about tinny times per minnie. 
These exiir rimeiifs were made, ilie w'lieel being 
excited hr one of Wollaston’s ten-plate ■l-incb 
troughs, the external magnet by another iioogli 
piecisely similai. On adding a second I oagli 
to the exiern.il magnet, the velocity liecame so la- 
pid we could with ditiicnlty coiiiii it by the eye. I be 
Velocity was similai l\ tiicieased in adding ibes.- 
coiid iiongh to ilie wheel in>icad of ilie external 
magnet. I'lie speed oi the wheel was also reniaih- 
ably inciensed, by conneciing wiili the baiterv the 
Second Spiral with wbicii the external o agm t was 
piovided. It is almost needless to mention lhai the 
inacliine was stopped at iileaMire l»y lemoving any 
one III the c<>nn»ciiiig wiiep, wlieinei of the wheel 
or of the exieinal magnet. In this state the model 
was shewn to seveiat ft lends , tind afte i wards exlii- 
bited at Liid Ancklaiid’s conv ei sa/.ioii6 on the 9tlt 
of Novembei. 
Remarks. 
The preceding description and drawings, 
together with the papers 1 may refer to in 
the Appendix, are quite sufficient to shew 
that the mechanism of this model is altoge- 
ther different from that of any electro-mag- 
netic machine hitherto invented, of which 
any account has been published. 
The pole-changer described by Mr. M’ 
Gauley is in principle the same as mine ; 
and had I received that gentleman’s paper 
when I commenced my experiments, I should 
not have deemed it necessary to construct a 
different one. My model was, however, 
finished and shown at Governm‘-n' House 
before I received the Philosophical Maga- 
zine containing tlie description in question. 
In all respects however, the detail- of these 
pole changer-r differ I’he mode of working 
the wires is peculiar to mine, and 'he glass 
tube- in mine serve the important end of guid- 
ing the wires to the mercurial surface, and 
preserving this from accidental derangement 
by the motion of the machine. 
The application of e’ectro-maanets to the 
direct attainment of a rotatory mo'icn being 
thus accomplished, and all intervening and 
weakening impediments of cranks, &c. alto- 
♦ Only one of the spirals of the external magnet 
was used in the Qist ixpei iiiieni. 
gether avoided, the question of course pre- 
sents itself, Can this motion be rendered 
sufficiently powerful ? and if so, can it be pro- 
cured at so economical a rate as to justify 
the expectation that it may be made availa- 
ble as a mechanical or locomotive agent ? 
It is but with the utmost self-distrust that 
1 would venture to discuss the first of these 
questions, since 1 cannot but be conscious 
that my knowledge of mechanics is too limit- 
ed to warrant my speculating on the subject 
but with the greatest caution. But 1 may 
perhaps be permitted to offer a few practical 
observations, in connexion with numerous 
experiments I have made and am still pursu- 
ing. 
Apparently the most obvious mode of in- 
creasing the power of the wheel would be by 
enlarging its diameter, preserving the same 
distance, two inches, betweenthe wheel mag- 
nets — by increasing at the same time the 
number of the wheel magnet, and diminish- 
ing the distance between each pair, say to 
one inch. 
A model was constructed with the view to 
determine experimentally the effect of these 
alterations. The wheel was 37§ inches in 
circumference, mounted with 32 magnets ; 
clear interval one inch. The arrangement of 
the disks, external magnet, and pole- 
changer, the same a-: before; — a uniform but 
extremely slow rotatmn ensued ; the pow er 
at the axle was very nearly the same as with 
the original model. Every alternate magnet 
was now removed, thus making the interval 
the same as in the first model ; the rotation 
became equally rapid, but the axle not more 
powerful than in the 12 magnet 8 inch 
machine. 
The sairte wheel was then fitted to a frame 
and series of supports, by means of which 
four external magnets, each of 30 lbs. power, 
with set arate pole-changers, were brought 
to net simultaneoushi on four sets of excited 
wheel magnets — viz. one set at each quarter 
of the wheel. 'I'lie experiments with this 
model were satisfactory but inconclusive. 
Each external magnet increased the power 
apparently in an arithmetical ratio; but hav- 
ing no more than five, sets of Wollaston’s 
plates at my disposal, I was unable to give 
ihe wheel magnets the fair quaniity of ex- 
citement which in the commenceraeni of this 
paper I have shewn them to require. I have 
little doubt that when sets of plates now in 
construction a'C completed, this form of 
model will work with four times the power of 
the first one, — or, in other words, lift 4 lbs. 
troy at its axle, the v.fheel revolving forty 
times per minute, 
A third model, on a different plan of com- 
bination, is now in construction. It consists 
of four vertical wheels, of the same dimen- 
sions as that in the first model, — all on one 
axle, and each wheel having an external prin- 
cipal magnet and separate pole-changer. The 
wheels and external magnets are so set that 
