The Advanced Student's Petrological Microscope, c. 1908
Among the accessories are
a single eyepiece, a 1-inch and 1/4-inch objective each
with canister, a divisible substage condenser, and the
polarizing Nicol prism in a rotating calibrated mount.
The analyzer prism is within the tube held by a
slide-in mounting. The Bertrand lens is accomodated
within the tube using a focusing sliding-in
Extracted from the
Journal of the Royal Microscopical Society,
This Microscope has
recently been further improved from suggestions of J.S.
Flett. The coarse adjustment is by means of patented
spiral rack and pinion the slow focusing adjustment by
a millimetre screw the milled head of which is divided
to read to 1/120 mm The glass covered revolving stage
has the edge divided to 360 reading to 5 by means of a
vernier The polariser is fitted with divided flange and
spring catch to indicate the crossing of the Nicol
prisms and is made to throw out of the optic axis when
required immediately above the polariser is fitted the
convergent system of lenses The analysing prism is
fitted in a metal box which slides into the optical
tube below this is cut an opening for the introduction
of a quartz wedge undulation plate or gypsum plate
Above the analysing prism is fitted a Bertrand lens
with telescopic adjustment by means of which the
interference figures are perfectly shown in thick or
thin crystals The tube of the cross webbed eye piece is
provided with an opening to allow of the use of a
quartz wedge or micrometer.
Within the case is a typed paper label reading: "This Swift petrological microscope number 14790 with accessories in the case belongs to and is the property of Angus Campbell Fraser". It is signed by his son F. J. Fraser with the date January 16, 1965.
Frank Jardine Fraser was
born in Wallasey, England on August 8, 1892. He was a
geologist living in Ottowa, Canada and was the author
of Geology of southern Saskatchewan, (Canada.
Geological Survey. Memoir, 176), 1935. His father
Angus, the original owner of the microscope, was born
in Gairloch, Scotland on June 11, 1844.