the condition of the air; and, in view of our present ignorance, it
would be wise to banish them from our sleeping apartments, at least
until we are better informed regarding their true properties."

* * * * *

PATENT OFFICE ILLUSTRATIONS.--We are indebted to Messrs. Jewett &
Chandler, of Buffalo, N.Y., for advance sheets of the illustrations
designed to accompany the Report of the Commissioner of Patents for the
year 1868. We have frequently had occasion to commend the skill and
fidelity of these illustrations. They are most admirably done, and the
value of our Patent Office Reports is much enhanced thereby. In fact
without these illustrations the reports would be of little value.

* * * * *




Improved Treadle Motion.


It is well known that the ordinary means employed to propel light
machinery by the foot are fatiguing in the extreme and although the best
of these is the rock shaft with foot pieces, employed almost universally
in modern sewing machines, this requires the operator to sit bolt
upright, a position very trying to the back, and one which has been
shown to be productive of weakness and even permanent disease.

The device shown in the engraving employs only the swinging motion of