and the lives of many of the inmates endangered. When the origin of this
fire came to be traced out, it was found that it was due to one brick
being left out in a flue. A penny would be a high estimate of the cost
of that brick and of the expense of laying it, yet through the neglect
of that pennyworth, £2,000 damage was done, and risk of human life was
run. I think there is a moral in this story which each of us can make
out if he will.

* * * * *

A fireproof whitewash can be readily made by adding one part silicate of
soda (or potash) to every five parts of whitewash. The addition of a
solution of alum to whitewash is recommended as a means to prevent the
rubbing off of the wash. A coating of a good glue size made by
dissolving half a pound of glue in a gallon of water is employed when
the wall is to be papered.

* * * * *




PHENOMENA OF ALTERNATING CURRENTS.

[Footnote: From a paper read before the recent meeting of the American
Institute of Electrical Engineers, New York, and reported in the
_Electrical World_.]

By Prof. ELIHU THOMSON.