--With regard to the Transit Circle, the new Collimators with
telescopes of seven inches aperture had been mounted. When the Transit
Telescope directed vertically is interposed, the interruptions in the
central cube impair the sharpness of definition, still leaving it
abundantly good for general use. It had been regarded as probable that
the astronomical flexure of the telescope, after cutting away small
portions of the central cube, would be found sensibly changed: and
this proved to be the case. The difference of flexures of the two ends
has been altered more than a second of arc.--Referring to a new
Portable Altazimuth which had lately been tested, the Report states as
follows: 'I may mention that a study of defects in the vertical circle
of a small Altazimuth formerly used by me, and an inspection of the
operations in the instrument-maker's work-shop, have convinced me that
the principal error to be feared in instruments of this class is
ovality of the graduated limb; this cannot be eliminated by two
microscopes, and such an instrument should never be fitted with two
only. Our instrument has four.'--'In Osler's Anemometer, a surface of
2 square feet is now exposed to the wind instead of one foot as
formerly; and the plate is supported by weak vertical springs instead
of rods running on rollers.
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