20 Scientific Societies. 



ravaged the fair face of humanity, and that we have sensibly 

 lengthened and materially improved the life of man ; and that 

 now, by the breathing of a liquid sprinkled on a handkerchief, 

 the unfortunate sufferer from the diseases or the accidents of life, 

 might lie happy and tranquil as an infant at the mother's 

 breast, while, in the new process of Iridectomy, the fine manipu- 

 lation of some skilled operator cut away a fragment out of the 

 coloured circle of his unquivering eye, or while the work of agony, 

 agonizing no longer, was being wrought on his unshrinking 

 limbs. Ten thousand such triumphs of majestic sorcery, ten 

 thousand such achievements of innocent enchantment, would have 

 shewn these ancient despisers of all physical research that it 

 was on these boughs, more than all others of the tiee of know- 

 ledge, that man (not now tempted by the serpent, but guided 

 and illuminated by the pointed finger of God himself) ]ilucked, 

 and plucked with perfect innocence, in largest and richest abund- 

 ance, " fruits which were fruits of nepenthe, and flowers which 

 were flowers of amaranth." 



And how, they would reverently ask, has all this been brought 

 about ^ Instead of giving you the answer, let me suggest it. 



The use of the chronometer for finding longitude by observa- 

 tions made on the satellites of Jupiter — the accurate determination 

 of the earth's exact ellipticity — the calculation of the problem that 

 " if the earth's diurnal velocity in turning on its axis were seventeen 

 times greater than it is, the centrifugal force at the equator would be 

 exactly equal to the force of gravitation, so that people there 

 would have just the same tendency to fall upwards as to fall 

 downwards" — these may seem astonishing and important results ; 

 and they are results which are daily applied in the concerns of 

 life. Yet to what were they all due ? Simply to the fact that an 

 intelligent Italian boy of eighteen, noticed during divine service the 

 swinging of the huge bronze lamp — which you may see to this day 

 in the cathedral of Pisa — and seeing that common, simple, every- 

 day phenomenon with open eyes, noticed that the great and the 

 small vibrations of the same pendulum are performed in the same 

 time, and depend solely on the length of the pendulum ;* so that 

 by measuring the time of the various oscillations he could calcu- 

 late from their swinging the altitude of the roof. That boy's name 

 was Galileo, and the patent fact which he noticed with an obser- 

 vant mind, led to, nay, in fact was, the most splendid discovery of 

 a very splendid life. 



Again, you know, that the very greatest and most universal of 

 all the generalisations of science is the discovery of the fact that 



• He discovered the isochronism of the penduhim hy comparing the time of the 

 oscillation with the beating of iis pulse. 



