122 the president's address. 



United States, and a binocular microscope was constructed and 

 figured in " Silliman's Journal " for 1853. Nachet also, as you 

 are aware, was highly successful as a maker of this form of instru- 

 ment, and our fellow countryman, Mr. Wenham, made such 

 further important improvements that this class of instrument is still 

 held in the greatest estimation by those microscopists who do not 

 need the very highest powers objectives can furnish. In the 

 binoculars in general use the images are, as you all know, inverted, 

 but a notice of this kind, which endeavours to treat of the progres- 

 sive advancement of our favourite instrument, cannot be allowed to 

 omit the mention of that form of binocular invented by Mr. J. W. 

 Stephenson, wherein the images are erect, and increased facilities 

 are thereby given for the easy exploration of minute structures 

 even with very high powers. Now, in looking back over that 

 period of time embraced by these few notes, we are enabled to 

 estimate the amount of interest which has actuated the minds 

 of men in striving after a more perfect knowledge of the nature 

 of Light and its various phenomena ; and it is worthy of notice 

 that an interest born in the dark ages of antiquity, and fading 

 not through rnediasval times, exists in its greatest intensity in the 

 present, and who can tell what the future may produce ? As the 

 laws of Light became better understood, so our means of seeking 

 the invisible became gradually more perfect, till the limits of 

 our illuminating power forbade the use of objectives higher than 

 Powell's Jq, but who shall presume to assert that, with the advent 

 of the electric light and improved immersion fluids, we shall not be 

 able to extend our vision into that world which we know lies beyond 

 the grasp of our present powers. It is but 140 years since the 

 first birth of Wilson's microscope — the crude and early parent of our 

 present form — and what is that length of time wherein to perfect 

 our microscopical appliances ? I doubt not but it will be con- 

 sidered too brief for much development, a period of adolescence in 

 the long life of the microscope, but a period long enough, it is 

 true, to bring it from a plain and primitive form to one in which, 

 by the combined endeavours of home and foreign scientists, it 

 presents a grand piece of mechanism contrived for every con- 

 ceivable purpose. I should be sorry to think we had attained the 

 utmost limits of our power of reaching further into the, at present, 

 invisible world which lies beyond the grasp of our -^ of an inch 

 objective, and which that barely touches ; but if so much has been 



