struments of the latest and most improved
types which we have constructed for some of the leading observatories as
mentioned in the text. We feel that this series of illustrations may not
only be of general interest, but also of service in helping to determine
further developments of modern astronomical and astrophysical equipment. We
have not thought it advisable to describe in detail the various instruments
of precision, which we have been called upon to construct from time to time
for the scientists in the astronomical as well as other branches of science
during the last ten years. As a rule every astronomer is interested in some
special line of research, which for a successful investigation requires a
special adaptation of the instrument he proposes to use, and in such cases
we are confident we can fill the requirements and shall be happy to
correspond with interested parties. We are in position to undertake the
design of special apparatus and can furnish sketches and estimates in
accordance with the suggestions of the customer on short notice in such
cases, where the importance of the prospective business will warrant it.
Among the various instruments which we have built, but which are not
included in this catalogue, we wish to mention, spectroheliographs,
planetary cameras, photographic plate holders, domes for observatories,
etc.

The optical parts which we furnish are of the highest degree of excellence
and are made for us by several of the most reliable firms in this line.

Mr. O. L. Petitdidier is closely located to our works, and during the last
ten years has supplied most of our objectives, etc.

It is and has been the aim of our firm to produce apparatus of the highest
grade and the constant growth of our business is a mute but eloquent
testimonial that our efforts have been appreciated by our customers.

We are glad to acknowledge our indebtedness to many of the foremost
astronomers, who have greatly assisted us by suggestions as to their
particular requirements, and by supplying certain of the photographs here
reproduced.

We take this opportunity to thank our customers for the favors rendered us
in the past, and trust that in the future these mutually pleasant relations
may be renewed.

[Illustration: A 101]

#A101. Alt-Azimuth Mounting# on strong hardwood tripod. The vertical and
horizontal axis have large bearing surfaces, assuring stability and
steadiness of motion. All parts excepting the trip