In the following pages we have endeavored to give to our customers an idea of the line of astronomical instruments 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 tripod head are made of brass and are nicely finished. The telescope is fitted with long rack and pinion motion. Three celestial eye pieces are included. Price with 2 1/2" telescope #$90.00# #A102.# The same as above with 3" telescope. Price #$110.00# #A103.# The same as above with 3 1/2" telescope. Price #$140.00#