172 THE TORNADO OF 1851. 



that, although individuals had experienced severe losses in their property at points farther 

 soutli in the track than that which was chosen for the starting-point of the survey, still, 

 as a whole, the violence of the storm had been most felt in those parts which are em- 

 braced within the limits of the map. Moreover, in no other part of the track are all the 

 varieties of surface so well displayed within the same limited extent. Emerging from a 

 thicket of forest growth, near the foot of Wellington Hill, in Waltham, the storm crosses 

 an open meadow, and commences the ascent of the hill. Then it passes along the crest 

 of the hill, meeting in its way houses and barns, orchards, cornfields, fences, and forests. 

 Now it commences its descent, and, as if gathering fresh strength at each obstacle, flies 

 with resistless violence through the town beneath, bathes its weary wings in the waters 

 of Spy Pond, cools its feverish breath by the demolition of an ice-house, and with 

 renewed vigor speeds its way through the heart of West Cambridge, over the plain to 

 the Mystic River. Here we have, within the space of a few miles, every variety of 

 surface and every kind of obstacle presented, better than in any other portion of the 

 route. To these considerations might be added the accidental circumstance, that this is 

 the part not embraced in the observations of other persons. The more southerly portions 

 of the track were reconnoitred, and the more northerly part, beyond the Mystic, in the 

 town of Medford, is the district which was principally embraced in the report made by 

 the Rev. Charles Brooks in behalf of the committee appointed by the citizens of West 

 Medford. No map of either of these portions has to my knowledge been published, 

 but in one way or another the subject has been brought before the public of this vicinity, 

 and to such the present map will serve as a connecting link. 



Before commencing the survey, I had satisfied myself by a preliminary examination of 

 various portions of the track, that the direction of the axis line lay between N. 60° E. and 

 N. 70° E. A compass was placed at the point of the axis line corresponding to 0, on the 

 marginal scale of distances on the map, and a line was started N. 70° E., and staked at 

 the distance of every hundred feet. This line was then prolonged with a graphometer, and 

 at the same time perpendiculars to it at each stake were run out on both sides, and 

 staked at every hundred feet. While one party was engaged in running the axis line, 

 others prolonged the cross lines as far as any trace of the storm's action could be found, 

 and still others were engaged in filling in the sections thus formed. The position of 

 every tree was determined by two rectangular coordinates, and the direction in which it 

 lay on the ground, or, if removed from its original place, the direction in which it had 

 been carried was determined with a compass. By these means, not only was perfect 

 uniformity preserved in the field notes, but, what was of equal importance, the axis 

 and cross lines being first laid down upon the map, the work of plotting was very much 



