_Telescope_, draw type, made of brass with acromatic lens, length 11 in. Incomplete, and maker not known. The second of the instruments described in _The Journal of Andrew Ellicott_ as an acromatic telescope. Used for taking signals, with sliding tubes, which draw out to about 15 in. It was considered to be remarkably good for its length, and showed the satellites of Jupiter very distinctly. Gift of Andrew Ellicott Douglass of Flagstaff, Ariz., in 1931. USNM 152085. _Transit and Equal Altitude Instrument_, made entirely of brass, with original lens now broken. The instrument is described by Ellicott in the following extract from _The Journal of Andrew Ellicott_: Preparatory to beginning the ten mile square [of Washington] a Meridian was traced at Jones' Point on the West of the Potomac. From this Meridian an angle of 45 degrees was laid off North Westerly and a straight line continued in that direction ten miles.... From the termination of this second line a third making a right angle with it was carried South-Easterly ten miles: and from the beginning on Jones' Point a fourth was carried ten miles to the termination of the third. These lines were measured with a chain which was examined and corrected daily, and plumbed whenever the ground was uneven, and traced with a transit and equal altitude instrument which I constructed and executed in 1789 and used in running the Western boundary of the State of New York. This instrument was similar to that described by Le Monnier in his preface to the French "Histoire Celeste." ... All the lines in this city in which I have been concerned were traced with the same instrument which I used on the lines of the ten mile square but as the Northern part was not finished when I left that place, I cannot pretend to say what method has since been pursued. Deposit of Andrew Ellicott Douglass of Flagstaff, Ariz., in 1931. USNM 152080. FIGURE 10. [Illustration: Figure 73.--Telescope used by Andrew Ellicott for his survey of the boundary between the United States and the Spanish territory of Florida. The instrument is signed "W. & S. Jones, 135 Holborn, London." USNM 152082.] ELLIS, ORANGE WARNER (18th century). _Theodolite_, about 1780, brass; horizontal circle 5 in., vertical circle 5 in., telescope 7-1/2 in., compass 3 in.; spirit level set into compass card; spirit level attached to telescope; fixed vertical circle; unsigned. Used by Orange Warner Ellis about 1780 in the surveying of the boundary between the United States and Canada, the area which is now Vermont. Acquired from Miss Mary N. Ellis of Chicago, Ill., in 1929. USNM 309596. FIGURE 74.