No. 29 London Microscope

A complete series of No. 29 microscopes is made covering the requirements for all purposes.

Every point in the design and manufacture of a microscope, which tends to make it efficient and serviceable, has been considered and incorporated into this microscope, but in such a way that the price remains moderate. The whole instrument is of particularly solid construction, so that flexure in the parts is obviated and wear through use is reduced to a minimum. For use in teaching and research institutions where instruments receive constant and hard use, this microscope will give the best possible service, both as regards convenience in use and in lasting properties.

The differences in the various models are in the stages and substages of which there are several forms.

They are so made that all apparatus, such as mechanical stages, condensers and dark ground illuminators, nosepieces, object glass changers and extra object glasses and eyepieces, can be added as occasion arises, without the necessity of returning the instrument for fitting. By this means the No. 29 London microscope can be purchased in its simplest form and built up as desired into a complete instrument for high power work.

The following is a specification of the microscope—

Base and pillar are in a heavy solid casting with large spread X 5Jin.), making the microscope stand firmly in either the vertical or horizontal position. The limb is hinged into the top of the pillar so that the instrument can be used at any angle from the vertical to the horizontal.

Limb is made in a solid casting, and is of an exceptionally robust construction and is shaped for conveniently lifting the instrument without risk of damage to the adjustable parts.

Stage is of extra large size, measuring about 4| in. square, so arranged that the distance from its centre to the limb is 3J in., so that the whole of a 6 in. petri dish or culture plate can be examined. Stage clips for holding specimen in position are provided. In model 29H the stage is circular, 4£ in. diameter and has centring and rotating movements.

Focussing adjustments. The microscope has a coarse adjustment, actuated by helical rack and pinion. The greatest care is taken in the perfect smoothness of working of the slides in which the body moves, so that any shake or backlash is obviated. Comparatively high powers can be focussed with it. The fine adjustment is of a very strong and effective design. It is constructed in such a manner that a smooth working focussing adjustment giving no backlash is obtained. It is actuated by two milled heads, one on each side of the limb, thus being readily accessible to either hand.

Body tube. This is of the standard length and has an extending drawtube, marked so that the tube length can be readily set at 160 m/m., for which the object glasses are corrected. If desired the drawtube can be graduated in millimetres at an extra cost. The model 29H is always supplied with a graduated drawtube.

Mirror. A double mirror, plane and concave, is fitted into the lower end of the limb. It is in a semi-circular fitting which rotates, and in which the mirror turns on its axis.

12

---

Le texte affiché peut comporter un certain nombre d'erreurs. En effet, le mode texte de ce document a été généré de façon automatique par un programme de reconnaissance optique de caractères (OCR). Le taux de reconnaissance estimé pour cette page est de 99,72 %.

La langue de reconnaissance de l'OCR est l'Anglais.

---