f the tide of discovery and
improvement, and that upon these subjects he shall _know_, not trusting
to mere hearsay or to unintelligent prejudice for his impressions.

Some little time since a gentleman from a neighboring city called upon
me for information upon the subject of coverings in general and their
comparative values. Being an intelligent man he said frankly at the
outset that he knew very little on the subject. He had, however, in
common with all of us, heard the word "asbestos" used as a shibboleth
for years, but he desired definite knowledge, and after he had digested
the information he should act on his judgment. I devoted sufficient time
to him to put him in possession of the salient points of the subject.
His understanding was acute. He left me to seek elsewhere further light
upon this matter. After some few days he returned and directed that the
magnesia covering be applied to his work. In the course of conversation
he remarked that he had received great diversity of advice from those to
whom he had gone. One man, who had been years in the business of selling
steam plants, told him that the best thing for him to use was hair-felt,
even though the steam-pressure might run up to 125 pounds to the inch.
Now, as a matter-of-fact, the man who gave that advice simply showed
himself an unsafe guide; and from his inability to keep abreast with
modern knowledge, that he had no conception of the fire-hazard which his
advice was to thrust upon the innocent inquirer, and that his advice was
little short of being morally criminal.

The subject of the fire-hazard of organic coverings has been pretty
thoroughly investigated and can be pretty well-known, when there is any
inclination to get out of ruts which long years of travelling in has
deepened. How many fires (cause unknown?) have really originated from
the slow carbonizing of organic material on steam-pipes? It is but
recently that the hair-felt covering on the steam end of a Worthington
pumping-engine, within ten miles of us, not only burnt itself but
destroyed some thousands of dollars worth of walnut lagging. Cases of
the combustion of these organic coverings are numerous and are
well-known.

Few appreciate the great loss of heat from uncovered or imperfectly
covered pipes. Many have an indistinct impression that there may
possibly be some slight loss. But there is in many cases an absence of
knowledge upon this subject where it should be complete. The most