NEW OR IMPROVED MEANS OF AND APPARATUS FOR ASCERTAINING THE ACTINIC POWER OF LIGHT
Year: 1880

page_text: LETTERS PATENT to Leon Warnerke, of Champion Hill, in the County of
Surrey, for an Invention of "NEW OR IMPROVED MEANS OF AND APPARATUS
FOR ASCERTAINING THE ACTINIC POWER OF LIGHT."
PROVISIONAL SPECIFICATION left by the said Leon Warnerke at the Office
of the Commissioners of Patents on the 15th January 1880.
LEON WARNERKE, of Champion Hill, in the County of Surrey. "NEW OR
IMPROVED MEANS OF AND APPARATUS FOR ASCERTAINING THE ACTINIC POWER OF
LIGHT."
This Invention consists in the use of mineral phosphorescent substances for
photometrical and actinometrical purposes.
The phosphorescent minerals, such as sulphide of calcium, barium, strontium, or
zinc, are enclosed between glass slips or glass discs to protect same from atmospheric
influence, or prepared on a flexible support that can be wound round a reel. Other
discs formed of translucent and suitably coloured substance of various transparency
are situate in close contact with luminous surface, and arranged in such manner
that by revolving or sliding the part of consecutive opacity transparent numbers
can be interposed between the luminous surface and small telescope or other
magnifier through which observation is made. Owing to the persistence of excited
luminosity the apparatus is arranged so that only part of the surface is exposed at
once, and the whole surface can be divided so as to enable 10 to 20 exposures or
more to be made, utilizing the property of phosphorescent substance to have the
excited luminosity extinguished by the rays of law of refrangibility. There is
also a disc of coloured transparent media made of gelatine or collodion or glass
suitably coloured, which when interposed between the luminous surface and source
of light the luminosity is extinguished, and consequently the apparatus ready for
the next observation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Leon Warnerke in the Great Seal Patent Office on the 15th July
1880.
LEON WARNERKE, of Champion Hill, in the County of Surrey.
"NEW OR
IMPROVED MEANS OF AND APPARATUS FOR ASCERTAINING THE ACTINIC POWER OF
LIGHT."
This Invention consists in the use of the mineral phosphorescent substances for
photometrical and and actinometrical purposes. The phosphorescent minerals, such
as sulphide of calcium, barium, strontium, or zinc, are enclosed between glass slips
or glass discs to protect same from atmospheric influences, or prepared on a flexible
support that can be wound round a reel. Other discs (formed of translucent and
suitably coloured substance) of various transparency are situate in close contact
with luminous surface, and arranged in such manner that by revolving or sliding
the part of consecutive opacity transparent numbers can be interposed between the
luminous surface and small telescope or other magnifier through which observation
is made. Owing to the persistence of excited luminosity the apparatus is arranged
so that only part of the surface is exposed at once, and the whole surface can be
divided so as to enable 10 to 20 exposures or more to be made, utilizing the
property of phosphorescent substance to have the excited luminosity extinguished
by the rays of low refrangibility. There is also a disc of coloured transparent
media made of gelatine or collodion or glass suitably colored, which when
interposed between the luminous surface and source of light the luminosity is
extinguished, and consequently the apparatus ready for the next observation.
Having thus far described the nature of the said Invention, and incidentally
intimated in what manner the same is to be performed, I will now proceed (aided
by the accompanying Drawings) to further and particularly describe and ascertain
in what manner the same is to be performed or carried out in practice, that is
to say :-
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents the actinometer complete.
Figs. 2, 3, and 4, various parts of same separate.
A is a circular disc, in which phosphorescent material is hermetically_sealed
between two glasses and kept in position by a support A¹. The brass tube B with
the partition C is superposed over the disc A, and by means of small screws and
corresponding grooves in the disc A is so fixed that it can be caused to rotate.
The partition C has a circular opening in it. There is also a lid D hinged to the
tube B, holding a small magnifier or telescope E and indicator G. The partition C
is made in order that only a small part need be exposed to the action of light at
each observation. The indicator G standing against a certain number printed on
the rim of the disc A shows what part of the disc has been excited. The
tube H is fitted inside the tube B; it has a bottom J made from two discs of thin
glass, between which is inserted semi transparent material distributed in such a
manner that to the observer by transmitted light it is visible as a series of discs
of increasing opacity, and shows a light number standing in the centre of a dark
ground. There are twenty such numbered discs, and two others L and K having
no numbers; L is obscured with some transparent material of green colour; K is
perfectly transparent and colourless; to use it the spring F is pressed and the
lid D is opened. The tube H, which can be easily revolved when acting on the
projecting ring, is so placed as to have the disc K corresponding with the opening
in the partition C; light can now freely act on the phosphorescent surface. When
the exposure is made the lid D is closed, the funnel E of the telescope is made to
approach as nearly as possible to the eye, and by acting on the rim M the tube H

page_text: is revolved. Consecutive numbers will then be visible through the telescope but of
diminishing intensity, till at last one is reached in which it cannot be distinguished.
The last visible number naturally will indicate the intensity of the light. When
the next observation is to be made, owing to the persistence of luminosity of the
portion previously used, it is preferable to use a fresh surface, and with this end in
view the disc A is revolved till the indicator G points to the next number. Ten
fresh exposures can be made by this means. If however the observations succeed
so rapidly that after the last exposure the first portion of the disc is still luminous,
the extinguishing process can be resorted to, and this is done by exposure through
the aperture L, which is filled by the material capable of extinguishing the
luminosity. The relative value of each number is calculated, and to facilitate
comparison at the back of instrument there are movable discs with numbers
indicating at once difference of intensity of any two numbers under investigation.
Having now particularly described and ascertained the nature and object of the
said Invention, and in what manner the same is to be performed or carried out in
practice, I hereby declare that I claim the Invention of "New or Improved Means
of and Apparatus for Ascertaining the Actinic Power of Light," substantially as
herein before set forth and described, wherein the important point or feature is the
use of phosphorescent substances for actinometrical purposes, substantially as
herein before described.
In witness whereof, I, the said Leon Warnerke, have hereunto set my hand
and seal, this Twenty first day of June, in the year of our Lord One
thousand eight hundred and eighty.
LEON WARNERKE. (L.S.)