364 



diately under the wall was removed. This was done with consider- 

 able care and uniformity, and as the excavation progressed, the wall 

 slowly and quietly settled down. This process was continually re- 

 peated until the wall was lowered forty-one feet, when frost suspended 

 operations last season. At the same time that the excavation was 

 going on within the well the masons were at work carrying up the 

 wall. The iron rods were extended within this wall to its top, but 

 their size was reduced to one and one-fourth inches diameter. The 

 brick wall had a battu towards the centre of half an inch per foot. 

 The object of this was to prevent the wall from binding or getting 

 wedged by the pressure of the earth. The result was as anticipated. 

 The wall was regularly and uniformly settled as the excavation was 

 made. 



The work was resumed last spring, and progressed satisfactorily 

 until the bottom of the curb was about three feet below the water- 

 surface, when it was found to be impossible to make the excavation 

 under the curb uniformly. The curb did not settle evenly, and 

 cracks were produced in the wall, also an unequal pressure from the 

 material on the outside was thrown on the wall, which produced an 

 eccentricity of about two feet in the diameter of the well. This 

 wall was allowed to remain in the position last indicated. Another 

 curb similarly constituted of timber, brick and iron, was constructed, 

 the interior diameter being thirty -five feet, the walls two feet thick, 

 and the height ten feet, besides the cutting edge, which is of wood, 

 and projects below the main wall one foot. This curb wall was 

 lowered in a manner similar to the first, until its top was one foot 

 below the surface of the water, giving a depth of twelve feet of water 

 in the well. , Work was suspended at this point, as the depth of water 

 obtained was considered sufficient. 



The method of making the excavation under water was some- 

 what novel, and entirely successful, reducing the expense of that 

 portion of the work very materially. A cylinder twenty inches 

 diameter, and forty inches long, with a closed top, was made of three- 

 eighths inch boiler iron. The whole was made air-tight, except the 

 bottom, which was left entirely open. In the toj) were two valves 

 opening upward. 



The lower edges of the cylinder were made thin and sharp. At- 

 tached to the top was a timber or stem six inches square, and 

 eighteen feet long, and at the top of this a suitable attachment was 

 made for a hoisting apparatus. The tackle of the derrick was 

 made fast to this, and the cylinder was lowered away into the water, 

 the valves were forced open and the air escaped. As soon as the 



