OPENING ADDRESS. 3 



determination of vapour densities, Fizeau and Foucault's original 

 revolving mirrors and toothed wheels, whereby the velocity of light 

 was first determined independently of astronomical aid, Daguerre's 

 first photograph on glass, and the earliest astronomical photographs 

 ever taken. To these may be added De la Rive's instruments for 

 statical electricity ; the actual table and appurtenances at which 

 Ampere worked ; and some contrivances as if fresh from the hands 

 of Faraday himself. 



Yet rich as is this part of our collection, and interesting as it might 

 be made in the hands of one versed in the history and anecdote of the 

 past, we must not linger even about these pleasant places. Indeed, a 

 museum of only the past, venerable though it might be, would be also 

 grey with the melancholy of departing life. For science should be 

 living, instinct with vigour and organic growth. Without a con- 

 tinuance into the present, and a promise for the future, it would be 

 like a tree whose branches are broken, whose growth is stopped, and 

 whose sap is dried. And if I may carry the simile a stage further, an 

 exhibition of the present, with no elements of the past, would be like 

 the gathered fruits to be found in the market-place, ready to hand, it 

 is true, but artificially arranged. But when past and present are 

 represented in combination, as has been attempted here, the very 

 newest achievements will be found in their natural places as ripened 

 and ever-ripening fruit in the garden from whence they have sprung. 



In reviewing the series of ancient, or at least now disused, instru- 

 ments, one thing can hardly fail to strike the attention of those who 

 are accustomed to the use of the modern forms. It is this how much 

 our predecessors managed to achieve with the limited means at their 

 disposal. If we compare the magnificent telescopes, the exquisite 

 clockwork, the multiplicity of optical appliances, now to be found in 

 almost every private, and still more in every public, observatory, with 

 those of two centuries past ; or, again, if we look at the instruments 

 with which Arago and Brewster made their magnificent discoveries in 

 polarised light, in contrast to those with which the adjoining room is 

 literally teeming, we may well pause to reflect how much of their dis- 

 coveries was due to the men themselves, and how comparatively little 

 to the instruments at their command. 



And yet we must not measure either the men or their results by this 



