On a universal indicator for microscopes.

  • Jacob Whitman Bailey
Date:
[1855]
Catalogue details

Licence: Public Domain Mark

Credit: On a universal indicator for microscopes. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    3/14 page 1
    ON ^A-OIj^il^fniSAL INDICATOR FOR MICROSCOPES. In the dnarterly Journal of Microscopical Science, vol. i, p. 34, an ingenious contrivance for registering the position of microscopic objects is described by Mr. Tyrrel; a modification of this, by Mr. Aymot is given in a subsequent number (I. c, vol. i, p. 301); and a still better arrangement for the same purpose, suggested Ivy Mr. Brodie and applied by Mr. Okeden to his microscope, is de- scribed at p. 166 of volume iii. of the same work. The last men- tioned device can scarcely be improved upon for convenience ; but there is one defect which is inherent to all these inventions, viz: that they are essentially selfish contrivances, of no use to any one but the owner of the particular instrument to which they may be attached. The object of the instrument I propose is more comprehensive than that of the Pinders above alluded to; being no less than to make a Universal Indicator by means of which an observer can so register the position of any number of objects mounted upon slides, that when these are sent to a distant correspondent the latter may be able by means of the Indicator to find at will any of these objects as easily as if he had the identical microscope and Finder by which they were at first recorded. If such a mode of recording the position of objects can be generally adopted that when the register is once made, the record and the ob- jects shall then be entirely independent of the original instru- ment and observer, and applicable to any microscope, it will tend to promote science not only by facilitating the interchange of specimens among naturalists, but it will give to each observer's col- lection when properly registered, a permanent scientific value and utility which it could have in no other manner. The plan I have adopted is to make upon an engraved card what may be considered as a transferable stage having guide lines by means of which the centre of the field of view of the microscope, and the position of a slide when any object upon it occupies this centre, may be given. Plate I. shows the Indicator complete. The centre of the field of view corresponds to the intersection of the horizontal line C D with the vertical line E, F. On the right and left hand of this cetilre the vertical axes B, and A', are placed at distances of Uhs
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image