26 
The resurvey of Long Island Sound now in progress, by the 
United States Coast and Geodetic Survey, has proved a present benefit. 
The preliminary work necessary for making a hydrographic survey of 
the Sound, being to a great degree like that required for your work, 
you sought and, by the courtesy of Prof. J. E. Hilgard, Superinten- 
dent, secured an arrangement whereby, for a consideration, one of 
the Coast Survey triangulation parties should work at the western end 
of the State and include in its work such points as you might wish 
triangulated. The officer in charge of this work was Assistant Ger- 
shom Bradford. ‘The number of triangulation points determined by 
him during the year was 59;-number of signals built, 16; number of 
measures of angles, 6,408. I desire to call your attention to the 
fact that the western part of this triangulation is based on a primary 
base line of the coast survey, namely: from Tashua to Bald Hill, a 
distance of about twelve (12) miles. 
The triangulation work executed directly by the Commission 
shows the following results: Number of triangulation points deter- 
mined, 59; number of signals built, 19; number. of angles observed, 
237; number of readings of instrument, 1,408; number of pointings 
of instrument, 4,245. This work was executed by Mr. John G. 
Bramley. ‘The instrument used was a new eight-inch repeating 
theodolite, reading by two verniers to ten seconds. It was made in 
accordance with your instructions, last winter, by Fauth & Co., of 
Washington, D. C. Beginning at the Faulkner's Island Light- 
house, the Commission party worked east to the Saybrook Light- 
house. All requisite data being available for a line from Faulkner’s 
Island Lighthouse to North Killingworth spire, it was used as a base 
line, the same having been determined by the Coast Survey in 1834-6. 
The third point of the triangle was chosen at Cornfield Point. We 
thus have a triangle whose sides are about eleven, twelve and four- 
teen miles in length. <A glance at the triangulation sketch shows 
how this large triangle is made useful for the determination of 
the smaller ones. Great accuracy ensues from the use of large tri- 
angles in any extended survey, and especially so in respect to your 
surveys where perfect meridian lines are greatly needed. 
Beginning at Rye spire, Mr. Bramley’s work extends east to Bell 
Island; except that Round Hill and Stamford Light were determined 
by My. Bradford. These points were, however, occupied by Mr. 
Bramley for several days. The two stations on Long Island were 
determined by Mr. Bramley. 
It is probable that the triangulation work is in conception bold 
