THE INCORPORATORS 179 
In 1858 experiments were begun in astronomical photography, 
which were carried on so successfully, that on the occasion of the 
total solar eclipse in 1860, observed in Labrador with the first 
telescope constructed especially for photographic purposes, a 
distinct difference was shown in the character of the limbs of the 
sun and the moon. In 1861 Rutherfurd constructed “a Cas- 
segrainian reflecting telescope with silvered glass mirror, having 
13 inches aperture and 8 feet focus,” but the necessity for fre- 
quent resilvering and the tremors caused by the location in the 
city interfering with good work, the reflector was abandoned 
after a short trial. 
Mr. Rutherfurd’s first astronomical paper was published in 
1862. In this he confirmed Clark’s discovery of the companion 
of Sirius, having found the object with his 11-inch telescope. 
The next season he made seventy-nine measures of position-angle, 
and thirty-eight of distance. These observations, added to those 
made at Cambridge and at Pulkowa, gave the principal basis of 
knowledge of this newly-found body for two years. 
In 1863 Mr. Rutherfurd published in the American Journal 
of Science his second scientific paper entitled “ Astronomical Ob- 
servations with the Spectroscope,” in which he gives the result of 
his observations and measurement of the spectra not only of the 
sun, moon, Jupiter and Mars, but also for seventeen stars. He 
continued his observations of the companion of Sirius, and also 
published a paper in 1863 on “ Observations on Stellar Spectra.” 
Not long afterward he began to employ photography in these 
investigations, and obtained a fine representation of the solar 
spectrum which he exhibited to the National Academy of 
Sciences in 1864. He further improved his apparatus by the 
use of extraordinarily delicate diffraction gratings, the secret of 
making which he learned for himself, and with these obtained 
results in the study of solar and stellar light that were unequalled 
until Draper entered upon the same field some years later. 
Even more interesting and important are the results which 
Rutherfurd obtained in the construction of telescopic object- 
glasses for photographing celestial bodies. After much thought 
