A. Guyoi on the Appalachian Mountain System. 159 
One of my first labors, on arriving in America, in 1848, was 
collect all the measurements of the ‘Appalachian’ system which 
then been published. Except the elevations determined for 
railroads and canals, nearly alt the more remarkable heights 
ich been measured were in New England or New York, 
that is 8 say, in the White, Green and Adirondack mountains. 
Add to this the secondary. heights measured, in considerable 
number, in Maine, New H ampshire and Massachu setts, a few 
points in Pennsylvania and Virgin Nee and some rather vague 
determinations in North Carding by Dr. Mitchell, and we have 
neer'y all the hypsometrical wealth then at the service of the geog- 
rapher. Massachusetts, the only state in the Union which has 
had a regular trigonometric survey, furnished besides some geo- 
he comparison of ess last soon led me to see in the heights 
published by different authors se differences as indicated either 
a confusion of names, or errors in measurement too consider- 
able to be attributed to the fotinciied employed in calculating, 
and which could only be attributed to imperfect ghar or 
to circumstances too unfavorable for the work which was under- 
taken. As for detecting the error, when there was a “disauteee 
ment, it was hopeless; for, since most of the authors gave merely 
their results, without the observations from which they were 
deduced, and without describing the instruments emplo 
the circumstances of the measurement, a discriminating criti- 
cism was impossible. Moreover, the measurements which I had 
occasion to verify were ee, all found to be affected ee errors 
Sines 1849, I have Aevctod 1 my summer excursions to a stat 
of the physical configuration of the Appalachian system, and to 
he barometric measurement of those points which were most 
rtant in me establishment of the laws of its relief. Ib 
wil the m g groups, namely, the so 
Mountains, + hare I made four excursions in as many different 
Lit 
fen, as my irons ne ya show, the eulminatiog Baits of 3 
acc «5 
