PROFESSOR LOVERIXG'S ADDRESS. 201 



the strength and accuracy which the battery and the balance have 

 given to chemistry, or on the stretch and precision of vision which the 

 telescope and microscope have bestowed on astronomy and physics. 

 These instruments, the veterans of many a hard-fought battle, science 

 still enjoys ; not superannuated by their long service, but continually 

 growing in power and usefulness. The little opera-glass with which 

 Galileo first lifted the veil from the skies and awoke the thunders of 

 the Vatican, has blossomed out into the magnificent refractors of Cam- 

 bridge, Chicago, and Washington. The little reflector with which 

 Newton, by a happy mistake, expected to supplant the lens, has 

 grown into the colossal telescopes of Herschel, Rosse, and the Mel- 

 bourne Observatory. The spasmodic, momentary action of Davy's 

 batteries, sufficient, however, to inaugurate a new era in chemistry, 

 has been superseded by constant currents, which grumble not at ten 

 hours a day. After lighting up the forelands of a continent during 

 the night, they are fresh to work an ocean-telegraph the next morn- 

 ing. With all my wonder at this mysterious instrument, which serves 

 so faithfully the cause of science and civilization, w T ith renewed ad- 

 miration of the microscope and the telescope, one of which transfoimis 

 an invisible speck of matter into a universe, and the other collects the 

 immensity of the heavens into a little celestial globe upon the retina 

 of the eye, I must pause for a moment to eulogize that simplest and 

 most modest of scientific tools, the pendulum. 



With the eye of science Galileo saw in the leaning Campanile at 

 Pisa, not a freak of architecture, but the opportunity of experimenting 

 on the laws of falling bodies ; and, in the adjacent cathedral where 

 others admired the marble pavement or the vaulted roof, the columns, 

 statues, and paintings, his attention was caught by the isochronous 

 vibrations of the chandelier, which during the long centuries has never 

 been absolutely at rest. When it is said that the pendulum has no 

 rival as a standard of length except the metre, that it furnishes an 

 exact measure of time, and that time is an indispensable element in 

 the study of all motion, and also the most available means of obtain- 

 ing longitude on the earth and right ascension in the heavens, a strong 

 case has been made out for the practical and scientific usefulness of 

 Galileo's discovery. During the long years of doubt in regard to the 

 true figure of the earth, the pendulum maintained the cause of New- 

 ton in opposition to the erroneous reports of the geodesists, until Mau- 

 pertuis, by a new measurement, flattened, as has been pithily said, the 

 earth and the Cassinis at the same time. The shape, rotation, and 

 density of the earth ; the diminution of terrestrial gravity with an 

 increase of distance from the centre ; the local attractions of moun- 

 tains, and secrets hidden below the surface of the planet, have been 

 discovered or verified by the declarations of the pendulum, which, 

 whether in motion or at rest, has never tired of serving science. And, 

 in a wider sense, the pendulum has done for the electric and magnetic 



