ADDENDUM. As the primary triangulation ties in the tertiary triangulation of the river between Little Rapids and Point Iroquois, tying directly to it at each end and at several of the intermediate stations, and as many of these tertiary stations were used by the topographers in the course of their season's work, we have, in accordance with your suggestion, procured from Assistant Engineer Joseph Ripley, who executed this work, his computations of the triangle sides-given in Table No. 4-and bave computed the geographical positions of the stations, and they will be found in Table No. 5. The tertiary system must have been executed with great care, for Mr. Ripley's length of the primary line, Iroquois-South Gros Cap, on which it closes, agrees with the primary value within 0.47 of a meter. His azimuth of this line also agrees with the primary azimuth within 16". These discrepancies have been distributed throughout the system, making it conform to the primary values, and it is the adjusted values that are given in the table. Very respectfully, your obedient servant, First Lieut. CHARLES S. RICHÉ, Corps of Engineers, U. S. Army. E. E. HASKELL, Stations. TABLE NO. 3.-Secondary points located from the primary system. Meters. Of Chippewa County. Mich. In Sault Ste. Marie, Mich. In Canal Park at Sault Ste. Marie, Mich. tain. Soo Soo 1,942. 38 8, 836. 57 1, 147. 85 3,326. 62 3, 413. 42 The iron flagstaff at New Fort Brady. A station of the river triangulation. In Sault Ste. Marie, Ontario, Canada. Do. 2, 099. 17 On the Shingwauk Home in Canada. 11, 930. 49 8,427.87 12, 687. 13 18, 894. 81 A station of the river tri angulation. |