1891.] MICROSCOriCAL JOURNAL. 27T 



first to give new life to microscopy in England, and made great pro- 

 gress in the improvement of the instrument, both optically and me- 

 chanically, and a glance through his " Micrographia " would readily 

 convince one of his knowledge of the use of the instrument and its ap- 

 plication to research. Herschel has referred to him (Hooke) as •' the 

 great contemporary, and almost the worthy rival of Newton." 



On February 6, 1672, .Sir Isaac Newton communicated to the Royal 

 Society his " design of a microscope by reflection," consisting of a 

 spherical concave speculum of metal, and an eye-glass which magnified 

 the reflected image of any object placed between them in the focus of 

 the speculum. 



Leeuwenhoek, the founder of histology, is prominent in the history 

 of the microscope during the latter part of the 17th century — about 

 1673. His microscopes were of the rudest construction mechanically, 

 while optically they consisted only of a bi-convex lens let into a 

 socket and a hole drilled into the plate for the e3'e to look through. 

 To quote Mr. Mayall, " his reputation as a discoverer in micro- 

 scopy was really based on his patience and dexterity in the prepa- 

 ration of his objects, and on the skill he brought to bear on the inter- 

 pretation of his observations." 



His investigations in histology were very great, as are shown in his 

 " Anatomia Interiora Rerum." Particularly noteworthy are his re- 

 searches on minute nerve structure and on the capillaries. With such 

 imperfect instruments and no methods of preserving histological ob- 

 jects, we can well marvel at the amount of his work and the accuracy 

 of his observations. 



While it is difficult to assign the microscopes of the latter part of the 

 17th centurv to chronological order, the period is remarkable for a large 

 number of instruments of various designs, prominent among them being 

 some excellent models of early English microscopes. Two quaint mod- 

 els, binocular, by Cherubin d'Orleans, respectively 1677 and 16S5, 

 Grindl's compound microscope, 1687, Bonnani, 1691, and Hartsoeker's 

 simple, 1694, and'Gray's " Water Microscope," 1696, consisting of a 

 plate of brass with minute holes in which drops of water were to be placed, 

 but without any arrangement for holding the object. Drops of water 

 were put in the minute apertures, forming a bi-convex lens of unequal 

 curvatures by which, with care, observations could doubtless be made. 



The first half of the iSth century records the names of many makers 

 of microscopes, and the period is remarkable for originality. John 

 Marshall's double microscope, 1702. A number of important innova- 

 tions in microscopical I'esearch are embodied in this — a fine adjustment 

 screw ; a ball-and-socket joint is employed with the advantage of in- 

 clining the entire microscope, and the first appearance of a condensing 

 lens. This instrument is employed with a candle beneath the con- 

 denser, from which it is inferred that the mirror used for reflection of 

 rays was at thi.s date still unknown. Musschenbroek had two curious 

 forms dating 1702. 



Culpeper make a number of models between the date of 1720-1740, 

 each model being a decided improvement over the previous ones. His 

 microscopes are all figured with the mirror. Scarlet's, Lieberkiihn's 

 solar inicroscope, Martin's Universal, and George Adams's Universal 

 Microscopes all appeared in rapid order prior to 175°' ^^^'^^ ^^""^ improve- 



