cause the lenses of the objective themselves to fluoresce, which would not fail to interfere with the observation by casting a general haze over the field. To obviate this the ultra-violet as emitted by the lamp should be so reflected at the silvered mirror as to fall on the preparation at an angle which amounts to little more than a grazing incidence. To achieve this the luminous crater of the lamp should be roughly on a level with the centre of the silvered mirror above the stage.

Preparations intended for observation in this way under the microscope must not be mounted in Canada Balsam as this is in itself an actively fluorescing medium.

The lamp is available for ordinary microscopic observations and for dark-ground illumination, it being in this case only necessary to withdraw the U. V. filter and the condenser for ultra-violet light from the lens and filter tube and to replace it by a condensing lens of the usual kind.

No. fe s. d. Codeword

116. Luminescence Lamp on Stand with Condensing Lens

for ultra-violet light, and U. V. Filter.............5. 0. 0 Lumen

117. Silvered Concave Mirror for Microscopic Observations

with the Luminescence Lamp......................... 0. 5. 0 Lumia

118. Luminescence Lamp on Stand with Silvered Mirror . 5. 5. 0 Luminatior

119. Ordinary Condensing* Lens fitting the tube attachment

on the Luminescence Lamp.............................0. 5. 0 Luminar

120. Liliput Arc Lamp for a current of 4 to 5 amperes on Stand. This lamp is of the hand regulating type and is for this purpose fitted with a geared ratio mechanism. It is one of the best and most convenient sources of light available for use in conjunction with Dark-ground illuminators, the Ultra Condenser, as well as the Vertical Illuminator.

The positive carbon, which supplies the luminous crater, is arranged in a horizontal position, which ensures that the centre of luminosity may remain immutably in the optic axis

The lamp may be operated from any electric house supply, to which it may be connected by means of a plug switch, a resistance being put in circuit with the lamp to suit the existing voltage. In orders it should be stated whether the lamp is to be operated by a continuous or an alternating current...........................1.10. 0 Liliput

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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 99,31 %.

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

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