366 
Transactions of the Society. 
VIII . — On the Evolution of the Tine Adjustment. 
By Edward M. Nelson, Pres. B.M.S. 
{Read 17 th May , 1899.) 
As there was no paper available for this evening, the occasion seemed 
suitable for supplementing my former paper on the coarse adjustment * 
by a dissertation on the line adjustment. There will, however, be this 
difference between the papers, viz. that in the former I had a new 
kind of coarse adjustment to bring before you, while in this I have 
no fresh design in view ; this paper will, therefore, in the main be 
historical, and as we go along we shall look out for any lessons or 
truths that can be picked up. 
The fine adjustments of early Microscopes, viz. those constructed 
towards the end of the 17th and the beginning of the 18th centuries, 
were of a very crude type, and need not detain us long. First, we 
have those of the Hooke (1) type, consisting of a wooden screw in a 
collar; this form covers a large number of Microscopes, viz. those 
constructed by Galileo ( 2 ), Bonannus ( 3 ), and Campani ( 4 ), and 
many more made at Nurnberg and Augsburg, date l(hi5-1700. 
Next, we have a simple screw, used by Leeuwenhoek (5), 1673, 
adopted by Musschenbroek ( 6 ) and Cuno ( 7 ), 1702, and in Smith’s 
(8) catoptric Microscope, 1738. 
Then there comes the brass screw barrel of Hartsoeker (9), 1694, 
and Wilson (10), 1702, a very popular foim. A tine example of one 
of these was presented this year to the Society by our Treasurer. The 
last of this type is the Wilson (11) screw barrel mounted on a scroll 
limb, made by Jones, 1798. At this time we also have the Wilson 
(12) compass Microscope, with screw-nut focussing, 1702, adopted 
by Joblot ( 13 ), 1718, and Lieberkuhn ( 14 ), 1740. Marshall’s ( 15 ) 
Microscope had a screw and a nut, 1704, and may come into this class. 
Next, we meet with a rackwork stage focusser in Hertel’s ( 16 ) Micro- 
scope, 1715 ; the rackwork is actuated by the right-hand ornamental 
butterfly nut in front of the stand ; the left-hand nut rotates the 
stage ; and the centre one gives it motion to and Irom the pillar. 
Passing over the Culpeper aud Scarlet ( 17 ), 1738, and the Benj. 
Martin ( 18 ) drum Microscope, 1739, which had no fine adjustments, 
we come to an entirely new pattern in Lindsay’s (19), which was a 
stage focusser by means of a lever; patented 1743, but alleged to 
have been made in 1728. 
We can now leave these elementary devices and pass on to the 
fiist good form of the early Microscope, which was undoubtedly that 
of Cuff (20) of 1744. Here we find a modification of Marshall’s, 
but one of altogether superior workmanship ; the nut is dispensed 
with, the screw itself being turned by the milled head. This Micro- 
* Journ. It.M.S., 1899, p. 256. 
