Cary, London (attributed), c. 1830

Gould's Improved Pocket Compound Microscope

Cary-Gould Pocket Microscope Cary-Gould Pocket Microscope
Cary-Gould Pocket Microscope Cary-Gould Pocket Microscope

Although this microscope is unsigned by the maker, it is identical to examples signed Cary, London.


cary_gould _microscope

Gould's Improved Pocket Compound Microscope. (Fig. 754, next page). The extreme portability and great magnifying power of this microscope will recommend it strongly to the naturalist, mineralogist, and botanist, as it has sufficient powers to discover minute animalcules and seed-vessels. It combines the uses of the single, compound, opaque, and aquatic microscopes; and has been found, upon comparison, by several scientific gentlemen, superior in power to, and more distinct, than many of the larger and more expensive instruments of the kind. It shuts up in a case, three inches by three and a half, and may be carried in the pocket without the slightest inconvenience.

Description of the Plate. A: The microscope, as it lies in its case, the body and pillars taken out, to show the apparatus beneath. B, the compound body. C, the pillar on which is fixed the stage, fig. 2, and reflecting mirror, fig. 3. These remain on the pillar when put into the case, for the convenience of packing. D, the arm, may be taken off and used as a hand microscope, fig. N. E, the different powers, Nos. 1, 2, 3. These are screwed on to the arm, and in them the body, but each may be used singly for large or opaque objects without the body. Nos. 1 and 2 may be combined: No. 3 is not to be combined with either, but used singly; the No. 4, in the small flat cell, is the higher power, and is to be used with or without the body for extremely minute transparent objects. F, the object-box, which unscrews to place live objects in, such as mites from cheese; this is placed on the stage. G, a movable piece, to place on the stage, fig. 2, for holding objects. H, slides filled with curious objects. I, a pair of steel-pointed forceps, which open by pressing the two brass pins, for holding flies, or pieces of card with opaque objects on them; this is placed in the hole on the stage or on the arm, when used as a hand microscope, fig. N. K, a dissecting-knife and point; a pair of brass forceps, for taking up small objects, with a spoon at the end for taking up a single drop of water, for placing between the two glasses to view the animalcule; a small brush for taking the mites from cheese, farina from flowers, and other delicate objects. L, the whole instrument put together for use. N, the arm converted into a hand-microscope. P, two pieces of glass sealed together for holding a drop of water. R, a circular piece of glass for placing on the stage G, to hold any object.

Directions for putting the Microscope together. First take out the pillar, on which is fixed the stage and reflecting mirror; screw it on the brass-piece on the side of the box; turn the mirror to face the light, and move the stage to the centre of the pillar by means of the rack and pinion; place one of the powers on the body, and screw it into the arm : you must now get a clear and distinct field; this you will obtain by moving the mirror to the proper angle to reflect the light, at the same time looking through the microscope; now place the object to be examined on the stage; get the proper focus of the lens by moving the stage up and down by means of the milled-head, fig. 9. To place the slides in the stage, press down with the fingers the brass spring underneath; as an improvement for viewing objects generally, the movable piece, G, is placed upon the fixed stage, fig. 2; it may be moved by the finger and thumb, with the greatest delicacy, in any direction; the object to be examined being placed upon the circular piece of glass. 'To place the pillar again in the case, let the stage be brought close up to the arm, and the mirror turned round; they will then fit into their place without being separated from the pillar. It is more difficult to get the reflected light with the candle than by day light, but many of the objects appear to much greater advantage; the candle should be placed at the distance of about twelve inches, not too high, and in a straight line with the mirror.

Description and Application of the Different Powers. This microscope has five different powers, so arranged that objects may be viewed from the size of a large beetle or moth to the most minute animalculee. These powers are marked Nos. 1, 2, 3; No. 1 is the lowest power, and is calculated for viewing opaque and large objects, and should be used without the body. No. 2 is the next power, and is calculated for viewing all the objects of the size of those in the slides; the next power is produced by combining the Nos. 1 and 2 together, which may be called the third power; it magnifies 2,500 times, and is adapted for viewing the animalculee, &c. The fourth power is in a conical cell, marked No. 3; with this power an object is magnified 26,000 times with the body; the fifth or greatest power is in a flat cell, and magnifies an object 62,500 times with the body, which is equal to the largest compound microscopes; it should only be used for extreme minute objects, and without either of the other powers; as the object and the lens come extremely near when it is used, care must be taken, by a very delicate movement of the stage, that they do not come in contact with each other in getting the proper focus. To prevent this, if a drop of water is to be examined, place it between the slips of glass, and if these will not permit the lens to come near enough, place a piece of thin talc upon a piece of glass. Objects should first be viewed with the low powers, that the whole of them may be seen, and the higher ones can then be used in gradation.

Also in this collection is a signed example of this pocket microscope and earlier one that is an uncommon variant of the usual design.

An essay about the William Cary business is online.

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