THE DAVON PATENT MICRO-TELESCOPG AND SUPEK 

 MICROSCOPE. 



Exhibited by F. Davidson. 



This apparatus combines in standardised and instantly inttr- 

 changeable iorm the functions of the microscope, telescope, camera and 

 projecting lantern for laboratory, educational and industrial purposes. 



The principle employed is the utilisation of an " air " image of a 

 more or less distant object projected to the plane of the microscope 

 stage by means of lens attachments which are inserted into the " Abbe 

 rim of the microscope stand, and tiien using the microscope itself as 

 an eye-piec8. 



Three different attachments are brought into requisition, viz. the 

 long focus attachment, the short focus ditto, and a micro object glass 

 forms the third. The first transforms the microscope into a telescope 

 with a range of vision of from six feet to infinity, and magnifications 

 of 20 to 50 diameters. The second is used for objects which, by reason 

 of their size or shape, cannot be examined on the stage of the micro- 

 scope, such as minerals, metal fractures, etc., the visual range being 

 from three feet to one foot from the stage of the microscope and 

 magnification from 30 to 90 diameters. The third in combination 

 with the microscope itself forms the super microscope. Magnifica- 

 tions of from 75 to 150 diameters with working distances of from 

 four to two inches or of 1,500 diameters with working distance of 

 ^ in, are characteristic features. 



Either attachment may be used for photography. With the first, 

 photographs have been taken at distances of 6 feet and 70 miles, with 

 the same combination; with the second, insects at from 18 ins. to 

 24 ins. ; and with the third attachment, photomicrography of a wide 

 variety of subjects at various magnifications from 1 to 3,000 

 diameters with excellent results. 



The outstanding feature of all views and all photographs is the very 

 great " depth of focus." This is so good that everything is shown in 

 apparent stereoscopic relief. 



The principle of photography with either attachment is the same, 

 and consists of substituting a camera for the body tube of the microscope 

 and virtually using a microscope objective as the eye-piece. No long 

 extension camera is therefore necessary, exposures are shortened and 

 vibration minimised in high power photomicrography. Photographs 

 of Himalayan Peaks 60 miles away, and blood corpuscles at a 

 magnification of 3,250 diameters have been taken in a ^ plate without 

 more than the ordinary extension. 



The illuminant is arranged in an optical lantern with a 4 in. 

 condenser and a supplemental condenser in a mount which fits the 

 Abbe " rim of the microscope. For projecting light on to a more or 

 less distant object the 4 in. condenser is used alone. For photomicro- 

 graphy the supplemental condenser only is used, while with the two 

 in combination effective micro-projection may be done without any 

 accessories. 



It is impossible in a briefly outlined description of the apparatus to 

 indicate the wide variety of uses to which the apparatus lends itself, 

 and it is no exaggeration to say that a new and wider field of observation 

 and utility is opened up in many directions. 



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