2a'« S. VI. 137., Aug. 14. '68.] 



NOTES AND QUEKIES. 



125 



arises from his readers knowing as little. It is 

 dangerous to attempt au attack on any knowledge 

 of which the assailant is ignorant, whether in ficti- 

 tious representation or sober argument. In our 

 own day we have had an assailant of the mathema- 

 tical sciences, of no mean name, who was so little 

 versed in the meaning of the most elementary 

 terms that, in an attempt of his own to be ma- 

 thematical, he first declares two quantities- to be 

 one and the same quantity, and then proceeds to 

 state that of these two identical quantities the 

 greater the one the less is the other. 



Swift's satire is of course directed at the mathe- 

 maticians of his own day. His first attack upon 

 them is contained in the description of the flap- 

 pers, by which the absorbed philosophers were 

 recalled to common life when it was necessary. 

 Now there is no proof that, in Swift's time, or in 

 any time, the mathematician, however capable of 

 withdrawing his thoughts while actually engaged 

 in study, was apt to wander into mathematics 

 while employed in other business. No such thing 

 is recorded even of Newton, a man of uncommon 

 power of concentration. The truth I believe to 

 be, that the power of bringing the whole man to 

 bear on one subject which is fostered by mathe- 

 matical study, is a power which can be, and is, 

 brought into action on any other subject : so that 

 a person used to mathematical thought is deep in 

 the concern of the moment, totus in illo, more 

 than another person ; that is, less likely to wander 

 from the matter in hand. Should any one of 

 your readers be prepared to name a mathema- 

 tician of whom he thinks that Swift's l^aputan is 

 a fair caricature, I will enter upon the point by 

 the help of existing biographies. 



Swift's technical knowledge is of a poor kind. 

 According to him, beef and mutton were served 

 up in the shapes of equilateral triangles, rhom- 

 boids, and cycloids. This beats the waiter who 

 could cover Vauxhall Gardens with a ham. These 

 plane figures have no thickness : and I defy all your 

 readers to produce a mathematician who would 

 be content with mutton of two dimensions. As 

 to the bread, which appeared in cones, cylinders, 

 and parallelograms, the mathematicians would 

 take the cones and cylinders for themselves, and 

 leave the parallelograms for Swift. 



The tailor takes Gulliver's altitude by a quad- 

 rant, then measures all the dimensions of his 

 body by rule and compass, and brings home the 

 clothes all out of shape, by mistaking a figure in 

 the calculation. Now first. Swift imagines that 

 the altitude taken by a quadrant is a length ; 

 whereas it is an angle. Drinkwater Bethune, in his 

 Life of Galileo, tells a story of a Cambridgeshire 

 farmer who made a similar mistake, confounding 

 the degree of the quadrant with the degree, 6ii 

 miles odd, on the earth's surface: by wliich ho 

 brought out strange conclusions as to the sun's 



distance. It is awkward satire to represent the 

 mathematician as using the quadrant to deter- 

 mine an accessible distance. Next, what mathe- 

 matician would use calculation when he had all 

 his results on paper, obtained by rule and com- 

 pass ? Had Swift lived in our day, he would have 

 made the tailor measure the length of Gulliver's 

 little finger, and then set up the whole body by 

 calculation, just as Cuvier or Owen would set up 

 some therium or saunis with no datum except the 

 end of a toe. 



According to Swift, the houses are ill built, 

 without a right angle in any apartment, from the 

 contempt the Laputans have for practical geo- 

 metry. Swift knew the ideas of the Platonic 

 school better than those of his own time, in which 

 a course of mathematics included almost every- 

 thing to which geometry or arithmetic could be 

 applied. Swift lived at the time which just pre- 

 ceded the separation, in the treatises, of pure and 

 applied mathematics : at the time in which this 

 separation was about to become an imperative 

 necessity. The great Cursus Matheinaticus of 

 Dechales (4 vols, fol.), of which the second edi- 

 tion was published in 1690, represents the idea 

 attached to mathematics in his youth. It contains, 

 besides what we should now call mathematics, 

 practical geometry, mechanics, statics, geography, 

 the magnet, civil architecture, construction of 

 roofs, cutting of stones, military architecture, hy- 

 drostatics, hydraulics, navigation, optics, music, 

 fireworks, the astrolabe, dialling, astronomy, as- 

 trology, the calendar. 



The touch at the belief in astrology, then not 

 uncommon among astronomers, is fair satire : but 

 Swift contradicts himself when he makes his ma- 

 thematicians strongly addicted to public affairs. 

 He speaks with great contempt of their political 

 opinions, which we may explain if we remember 

 that Swift was a Tory, and the most leading ma- 

 thematicians were Whigs. His arithmetic is good. 

 His diameter of 7837 yards does give his 10,000 

 acres; and his satellites of Mars are correctly 

 placed, so as to have the squares of the times as 

 the cubes of the distances. I have no doubt he 

 was here helped to the true answers. That Swift 

 could himself extract a cube root, or use loga- 

 rithms, is more than Apella would have believed, 

 even after twenty years' service in the marines. 



The college of projectors satirises a peculiar 

 class of men, of whom few are to be found among 

 well-informed mathematicians. Swift has made a 

 sad bungle of the only case in which he had to 

 use technical terms : — 



" Tliere •>vag an astronomer who had undertaken to 

 place a sundial upon the great weathercock on tlie town 

 house, by ailjusting the annual and diurnal motions of the 

 earth and sun, so as to answer and coincide with all acci- 

 dental turnings of the wind." 



■\Vhat this may satirise I cannot guess. Did 



