The Locomotive - Lighthouse Survival Blog

1901] THE LOCOMOTIVE. -j^
of so much stress that one anticipates a crash as the glass touches the cool iron of the
mold, but there is absolute silence — not so much as a hiss or the sound of the splash.
There is sometniug indescribable about the fluidity of this muss. It. seems thick like
oil, and yet it spreads more swiftly than water; it is more like quicksilver than anything
else that one can think of, and yet not at all like quicksilver.
The mold, with the glowing lens inside, was now covered with a plate of iron,
wheeled to the mouth of the cooling furnace, and lifted with chain tackle to the height
of the furnace floor. A movable-frame tramway was then placed underneath it, and it
was quickly pushed into the furnace. "Workmen were ready with brick and mortar, and in
ten minutes the lens was walled in. Here it is cooled for two weeks, and then brought
again to the open air, dull and milky of surface, and possessing only the general shape
of a lens. After that, for days and weeks, workmen are employed in polishing it, not
to give it the final form which it will have in the great telescope, but merely to prepare it
for that important and anxious day when it will be submitted to those searching tests
for imperfections, during which it must pass even the close scrutiny of microscopic and
spectroscopic examination. A few bubbles it may have and pass, for bubbles have no
effect, except to reduce the passage of light in a minute degree; but veins, denoting the
improper mixture of the ingredients of the glass, it must not have. If it passes all the
tests— and sometimes it requires many castings and costs many rejected lenses of this
most precious of glass before the necessary perfection is attained — it-is again sent to
the furnace house, where, with even greater care than before, it is slowly raised to a
high temperature, and thus annealed, and then as slowly cooled for two months or
more. After that it is ready for the lens-maker proper, that skilled mechanician and
mathematician of Jena or of America or of France, who polishes down its sides with
infinite care, until they reach the most perfect curves appropriate to the refraction and
dispersion of the glass disks employed. Each of these processes has absorbed precious
time and has cost much money; the bare glass for such a lens would cost about $5,000.
To this the skill of the optician would add, in polishing, perhaps $20,000 more, so that
the finished lens, ready for fitting into the telescope tube, would represent an expendi-
ture of some $25,000. Through such pains and expense as this must science pass, that
mankind may add a few facts to its knowledge of some distant star.
The German workmen are standing back from the cooling furnace, perspiring, the
lens finally cast. A boy comes in with li is apron full of beer, a bottle for each, and
they drink in characteristic German fashion to the success of the work. It may be
many a day before such another lens is cast.— Ray Stannard Baker in McClure's
Magazine.
The Hall of Natural History at Trinity College.
On December 7th the new Hall of Natural History of Trinity College, Hartford,
Conn., was formally opened. The Rev. George Williamson Smith, D.D., president of
the college, delivered the address of welcome, as follows: " It gives me great pleasure
to welcome you to Trinity College on this occasion. It is the realization of what was
undertaken by the trustees of Washington College, when they issued their prospectus in
1824. In that prospectus we find that professors had been appointed for departments
of chemistry and mineralogy, of agriculture and political economy, and of botany. A
professor of natural philosophy was to be appointed at an early day. It was a radical
departure of the college curriculum accepted at that time, to ijive such a large place to
scientific study, and the difference was increased by a provision that students could be