Baden Powell Unilens

Telescope attachments were not uncommonly available for walking sticks where two lenses (an eyepiece and an objective) were clipped to the stick shaft and focussed by moving one lens back and forth. Effectively being a telescope without a draw tube.
Major Baden Powell patented a single lens (Number 15563) in 1906 which he claims to work in similar fashion, but without an eyepiece lens. Unfortunately he gives no details as to how it works, neither in the original patent nor his supplementary patent number 22782 filed the following year.
The Elementary Theory of the Symmetrical Optical Instrument by J G Leathem, printed in 1908 notes:
“is a single lens which, when held at a distance of three or four feet from the eye, performs the function of a field glass and gives an upright magnified image of distant objects...single convex lens of about six feet focal length, so that when it is being used the eye is between the lens and the principal focus. The image of a distant object is therefore a real inverted image, behind the principal focus and therefore behind the eye. The pencils which are on their way to form this image are intercepted by the lens of the eye, and the eye accommodates itself to receive the resulting image on the retina. The accommodation required is that of the same kind as that...to view distant objects, but it is exaggerated to an extent which may be called accommodation for objects beyond infinity. The manufacturers state that only three people out of four can use the unilens; the use of the instrument is found to tire the eye.”
Uncorrected refractive errors will modify the nominal magnification of astronomical and Gallilean telescopes but the accommodation required by the Unilens would not be enough to give significant magnification.  Increased accommodative effort would cause the brain to believe the object viewed was at a different distance causing it to resize the mental image but this would cause minification, not magnification as occurs with the ‘Moon Illusion’.
Does anyone know if the Unilens does actually work and if so why? No prizes for anyone who can work out a ray diagram, but it would be much appreciated.
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