practice, and points out as the distinguishing feature of American
locomotives and rolling stock the bogie, or swiveling truck. "Keeping
in mind the distinguishing merits of the bogie, the other differences
between English and American locomotives are differences more of costume
and of toilet than of vital principles of construction."

The author attributes the origin of the greater subdivision of rolling
weight and consequent coupling of wheels on American roads to the
comparatively weak and imperfect permanent way, estimating the maximum
weight per wheel as being for many years four English tuns, while three
tuns he considers, as more than the average for each coupled wheel of
American locomotives.

To follow the author through the whole of his able paper, and the
discussion which it elicited, would occupy more of our space than we
can spare for the purpose. We will, however, give in the author's own
language, an account of an experiment conducted by him in 1855 on the
Erie Railroad.

"In the autumn of 1855, the author, at the request of Mr. (now
General) M'Callum, the manager of the Erie Railroad, took charge of an
experimental train, which he ran over the whole length of the line and
back, a total distance of nearly 900 miles. The same engine was employed
throughout the run, occupying in all nearly three weeks, making an
average for each week day of about 50 miles. The line is divided into
four divisions, varying considerably in respect of gradients, and the
utmost load the engine could draw was taken in both directions over each
division. The maximum inclinations were 1 in 88. The results of the
experiments were so voluminous, that it will be sufficient to detail
the particulars of what may be termed crucial tests of adhesion and