ALTITUDES, CONTOUR LINES, AND RAISED MAPS. 347 
form of the surface of New Hampshire by these lines will serve to call the attention of 
our people to the value of such work, and ultimately lead to a detailed topographic sur- 
vey and map. 
"The same information respecting the altitude and contour of the whole state, which 
is shown by these lines on the maps in the atlas of this report, has been otherwise and 
more noticeably displayed by a model or raised map of New Hampshire, the original of 
which has been placed in the vestibule of the state-house at Concord. The museum of 
Dartmouth college has a copy moulded from this, and others might be easily made. It 
will be seen, however, that the construction of the first model, to show all our principal 
mountains, hills, and valleys, involves a large amount of painstaking labor. This re- 
lief has a scale of one inch to a mile in distance horizontally, and of one inch to 1,000 
feet in height, making it about fifteen feet long, with Mt. Washington a little more than 
six inches high. The elevation is five times too great, as compared with the extent,— 
this exaggeration being necessary to give any prominence to the numerous hills less 
than 1,000 feet in height. 
A map on the horizontal scale of the proposed model was first drawn, by enlargement 
from the draft of the new state map, with contour lines for each 500 feet above the sea. 
Tracings of these lines were then made and transferred to boards of pine or basswood 
half an inch in thickness, corresponding on the scale of height to 500 feet. The boards 
were then sawed to the irregular form of the successive contours. Upon each set of 
boards, the line next above that followed in sawing was also drawn, and showed the 
exact position to be occupied in placing them one upon another to build up the high- 
lands and mountains. The projecting upper edges of the layers of board were then 
bevelled to a continuous slope, or cut into the hills and valleys required by intermediate 
lines of contour. The surface is painted, showing township lines, streams and ponds, 
railroads, etc., with their names, and those of villages and mountains. 
In the study of the modified drift, a large amount of levelling has been done, princi- 
pally along Connecticut and Merrimack rivers. The heights of all the terraces in both 
these valleys north of the Massachusetts line have been accurately determined, and are 
shown on Plates I-VI of this volume. Heights of these rivers and of localities near 
them were also determined, and are given, with the elevation of the highest terraces, 
on pages 39, 59-61, and 102 and 103. The most important corrections from altitudes 
along these rivers, published in Volume I, are in regard to the height of a portion of 
Connecticut river, which at Brattleborough is 200, at the mouth of Ashuelot river, 185, 
and at Massachusetts line, 180 feet above the sea (corrected from Vol. I, pp. 304 and 
319) ; and the height of Pemigewasset river at the mouth of the east branch, which is 
710 feet above the sea (corrected in this volume, p. 70, from Vol. I, pp. 288, 308, and 
322). The height of Winnipiseogee lake obtained by levelling (pp. 103 and 125) sug- 
gests the possible need of a still more important correction to be applied to nearly all 
the connected series of altitudes determined by railroad surveys in the western and 
northern parts of the state, published in Chapter X of Volume I. These altitudes 
may be said to be reckoned from Concord depot as a starting-point, which appears 
