Dollond, London

Cuff's New Constructed Double Microscope, c. 1765

Dollond London, Cuff's New Constructed Double Microscope, c. 1765

Dollond London, Cuff's New Constructed Double Microscope, c. 1765

    Dollond London, Cuff's New Constructed Double Microscope, c. 1765

Dollond London, Cuff's New Constructed Double Microscope, c. 1765

    Dollond London, Cuff's New Constructed Double Microscope, c. 1765

Dollond London, Cuff's New Constructed Double Microscope, c. 1765. case

Dollond London, Cuff's New Constructed Double Microscope, c. 1765. In the case
Dollond signature

Dollond London, Cuff's New Constructed Double Microscope, c. 1765. Stage

Dollond London, Cuff's New Constructed Double Microscope, c. 1765. Draws

 

An early proponent of the use of the microscope for scientific studies was the naturalist Henry Baker (1698-1774). In 1743, he published a popular work entitled The Microscope Made Easy, which was followed in 1753 with the publication of a second work entitled Employment for the Microscope. In two Parts. At that time, he lamented on the fact that the microscopes then available, primarily the Culpeper form, were deficient both with respect to their method of focusing and to the access that they allowed to the stage of the microscope. This inspired John Cuff (1708-1772), a London instrument maker, in 1744 to come up with his own unique design for a microscope, which was known as Cuff's New Constructed Double Microscope . This design allowed the stage to be freely accessible to the hands of the user and it incorporated a fine adjustment mechanism that allowed for more precise focusing. This form became extremely popular and was copied by many of the major instrument makers both in England and on the Continent.

The particular example in this collection was sold by Peter Dollond (1730-1820) most likely within the 1760-1770 time frame. In most respects, it conforms very closely to the original Cuff design (some references have suggested that some Cuff type microscopes signed by Dollond were actually made by John Cuff). An identical instrument dated 1761 is in the Science Museum, London collection. The function of the microscope and the accessories with which it was supplied were described and illustrated in the aforementioned 1753 Baker publication as follows:

 

"The cumbersome and inconvenient Double Microscopes of Dr. Hook and Mr. Marshall, were many Years ago reduced to a manageable Size, improved in their Structure, supplied with an easy Way of enlightening Objects by a Speculum underneath and in many other respects rendered agreeable to the Curious, by Mr. Culpeper and Mr. Scarlet. Some farther Alterations were however wanted to make this Instrument of more general Use, as I fully experienced in the Year 1743, when examining daily the Configurations of Saline Substances, the Legs were continual Impediments to my turning about the Slips of Glass; and indeed I had found them frequently so on other Occasions Pulling the Body of the Instrument up and down was likewise subject to jerks, which caused a Difficulty in fixing it exactly at the Focus: there was also no good Contrivance for viewing opake Objects. Complaining of these Inconveniencies, Mr. Cuff, the Optician, applyed his Thoughts to fashion a Microscope in another Manner, leaving the Stage entirely free and open by taking away the Legs, applying a fine threaded Screw to regulate and adjust its Motions, and adding a concave Speculum forObjects that are opake.

The foregoing Examinations having been all made by an Instrument thus improved, I shall give a Plate and Description of it, (as an Addition to my former Book on the Microscope) by the Name of Mr. Cuffs new constructed Double Microscope.

All Parts of this Instrument are Brass. - The Body A, being firmly supported in a broad circular Collar at the End of the Arm a a, which projects from the Top of the Pillar C, may be taken out or put in at Pleasure.

A square Box b b, screwed down to the wooden Pedestal 11 supports the whole Machine by the Assistance of, the long flat-square Pillar B, which is fixed within the said Box.

 

John Cuff microscope

The moveable Pillar C, which is shorter than the Pillar B tho' of the same Shape, by sliding up or down against the broad flat Side of the said Pillar, raises or lowers the Body of the Microscope as occasion may require. Both Pillars stand in the Box b b.

The square Collar D holds the two Pillars B and C together, and slides up or down upon them, carrying with it the Body of the Microscope. The Screw-Button 3 is intended to fix the Pillar C, when the upper Edge of the Collar D being set at the same Number as that of the Magnifier employed, its focal Distance is brought nearly right.

When the Pillar C is fastened, the Microscope (by the fine-threaded adjusting Screw E) may be moved so gently up or down, without Jerks or Slips that the true Focus may be found with great Readiness and Exactness.

The horizontal Plate or Stage F, having in the Middle thereof a circular Hole 4, directly over which the Body of the Microscope is suspended, is exceedingly convenient to place Objects on for Observation, being freed entirely from the Legs which encumber other Double Microscopes.

The concave Looking Glass G, turning on two small Screws in the Arch d (at the Bottom of which a Pin goes down into the Hole e in the Pedestal) reflects the Light of a Candle or the Sky directly upwards on the Object, by moving the Looking Glass horizontally or vertically.

A double convex Lens H, turns on two Screws, for transmitting Light to assist in illuminating opake Objects, when the long round Wire f is placed in the Spring-Tube g, at the Corner of the Stage F.

I-- is a hollow Cylinder whose sides are open, and at whose End a concave Silver Speculum h, having a round Hole in the Midst thereof, is screwed. This Cylinder flips over the Snout i of the Microscope, and when set to the Figure there marked, and correspondent to the Number of the Magnifier made use of, the Silver Speculum reflects Light on the opake Object to be examined; which Object must either be held in the Spring-Tongs at one End of the Wire O, placed in the Slit m on the Stage F; or be put on the Ivory Block P, stuck on the pointed End of the said Wire. The third or fourth Magnifiers are fittest to be used with the Silver Speculum.

K. L. M. N. QQ. R. S. T. V. W. X. Y. Z. are different Parts of the Apparatus which I think needless to describe, as all who are acquainted with Microscopes will know them at first Sight, and others may inform themselves either in my former Treatise on these Subjects, or in the Book which Mr. Cuff gives to those who buy this Microscope of him."


Views through the microscope of two specimens between mica disks on an ivory slider:

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