PERPENDICULAR 



PERPETUAL MOTION 



59 



Latin essay, graduated B.A in 1845, and was 

 elected Fellow of his college in 1849. He was 

 afterwards examiner for the classical tripos, select 

 preacher, Hulsean lecturer ( 1868 ), and Lady 

 Margaret's preacher ; professor in King's College, 

 London ; and from 1862 till 1872 vice-principal 

 of St David's College, Lampeter. Later he was pre- 

 lector in Theology and Fellow of Trinity College, 

 Cambridge ; preacher at the Chapel Royal, White- 

 hall ; and canon residentiary of LlandafT from 

 1869 to 1878, when he was appointed Dean of 

 Peterborough. Already, since 1875, lie had l>een 

 also Ilulsean professor of Divinity at Cambridge, 

 and an honorary chaplain to the Queen. In 1891 

 he succeeded Dr Philpott as Bishop of Worcester. 

 I)r Perowne is a sound Hebrew scholar, sat 

 throughout in the Company for the revision of 

 the Old Testament, and has lieen general editor 

 of the admirable series of .short commentaries 

 forming 'The Cambridge Bible for Schools. ' His 

 principal work is his commentary on the Book of 

 PicUms (2 vol. 1864-68), a masterpiece of exe- 

 getical science. Besides sermons and contributions 

 to magazines, other works are his Hulsean Lectures 

 on Immortality ( 1869), and Lampeter and Llandatf 

 Sermons (UTS). 



Perpendicular, the name given to the style 

 of Gothic architecture in England which succeeded 

 the Decorated style. It prevailed from about the 



Wincherter Cathedral Nave, looking west. 



end of the 14th century to the middle of the 16th 

 rcntnry, and wax thus contemjiorary with the 

 Flamboyant *tyh.- in France. These styles have 



much in common, but they derive their names 

 from the features peculiar to each. Thus, the 

 Flamboyant (q.v. ) is distinguished by the flowing 

 lines of its tracery ; whilst the Perpendicular is 

 remarkable for its stiff and rectilinear lines. The 

 lines of the window-tracery are chiefly vertical, and 

 the mullions are frequently crossed by transoms or 

 horizontal bars. The mouldings are usually thin and 

 hard. The same feeling pervades the other features 

 of the style ; the buttresses, piers, towers, &c. are 

 all drawn up and attenuated, and present in their 

 shallow recesses and meagre lines a great contrast 

 to the deep shadows and Imld mouldings of the 

 earlier styles. The art of masonry was well under- 

 stood during the Perpendicular period, and the 

 vaulting was admirably built. Fan-tracery Vault- 

 ing (q.v.) belongs to this style. The depressed or 

 four-centre arch is another of its peculiar features. 

 In doorways the arched head is frequently enclosed 

 in a square panel over the arch, with spandrels 

 containing shields, quatrefoils, &c. Panelling was 

 also much used, the walls being frequently almost 

 entirely covered with it, as in Henry VII. 's Chapel 

 at Westminster. There are many well-known 

 buildings of this style. Most of the colleges at 

 Oxford and Cambridge belong to it, and in almost 

 every cathedral and church of importance there 

 are some specimens of it e.g. William of Wyke- 

 ham's nave at Winchester (q.v.). Open timber- 

 roofs are very common in the Perpendicular style, 

 and are amongst the peculiar and beautiful features 

 of the architecture of England. The roof of West- 

 minster Hall, built by Hichard II., is the largest 

 example ever erected. 



Perpetual Cure. See CURATE, VICAR. 



Perpetual Motion. Formerly the attempts 

 made to 'square the circle' led to an enormous 

 waste of time till mathematicians proved, by 

 repeated and unassailable methods, that the cir- 

 cular area cannot possibly be -expressed in terms 

 of the diameter or radius. It logically follows from 

 the definition of a circle that it is a plane figure 

 which does not admit of being squared. In the 

 same wav, to all who have understood the words 

 force and motion, it follows from the definition of 

 a machine that it does not admit of being 'per- 

 petual,' or self-moved. Every machine is coik- 

 structed to transmit motion or force. The machine, 

 further, modifies the transmitted force, so as to 

 overcome certain resistances, some ' useful ' and 

 some 'prejudicial.' In every instance the motion 

 of the machine is derived from without, and the 

 energy so conveyed is to be at once referred to 

 muscular action, or the weight of falling water, 

 or a current of air, or the expansive force of steam, 

 or some other natural power. Some such force is 

 at once implied by the action of any machine, 

 whether the motion is only commencing or has 

 continued for an indefinite time. In an ordinary- 

 clock, for example, action is due to the muscular 

 force expended in coiling a spring or raising a weight. 

 The sight of motion in wheels or levers compels 

 us to l>elieve that force has been exerted upon 

 them, and that they are merely vehicles for trans- 

 mitting it. The machine has gained so much 

 motion and energy, but only at the expense of 

 some exterior agent. The quantity of force in 

 existence being fixed, no new stock can be created, 

 and therefore a self-moving machine is absurd even 

 in name. The practical engineer knows that the 

 force of his steam-engine is exactly in proportion 

 to the amount of coal burned per hour i.e. the work 

 depends on the consumption of heat. If the mechan- 

 ical force produced is in excess, however small, of 

 its equivalent ( measured by the coal banted ), then 

 perpetual motion would he at last found, because 

 then the engine would be generating force i.e. 



