OF ARTS AND SCIENCES. 295 



put on record the temperatures of other sources of water opened in 

 and near this limited drift bed. 1st. In a spring sunk to about the 

 depth of ten feet from the surface, — a stone's throw northwest of the 

 frozen well, at the side of the lane leading out of the main road, — 

 the water at top stood at 54° F,, and that near the bottom, at 50°. 

 2d. A similar spring about twelve feet deep, three or four rods west 

 of No. 1, showed a temperature of 50° in water drawn from the 

 bottom. Both these small wells are evidently fed by surface water, 

 and, at the time of our visit, they were filled nearly up to the level 

 of the ground. 3d. In a shallow spring at some distance southwest 

 of the frozen well, in lower ground, and apparently near the limit of 

 the drift, the water stood at 48° F. A deep well in the mica slate 

 formation, about half a mile west, stood at 45° F. 



It is to be hoped that the well, and the bed of frozen gravel in which 

 it is situated, may be made the subject of careful experimental inves- 

 tigation. It would, of course, be interesting to ascertain the precise 

 limits and conditions of variation in the current of air. It is also 

 desirable that the contour of the drift heap and the grounds adjoining 

 should be accurately determined. 



Four hundred and ninety-eighth meeting. 



September 10, 1861. — Monthly Meeting. 



The President in the chair. 



The Corresponding Secretary read letters relative to the ex- 

 changes of the Academy. 



Professor Horsford illustrated the several methods recently 

 suggested and employed for rendering linen and cotton fabrics 

 uninflammable. 



Professor Peirce made a communication upon the discrep- 

 ancy between the observed and the calculated acceleration of 

 the moon's motion, and the question whether it may be due 

 to the influence of meteoric bodies about the earth. 



Mr. Swett exhibited a piece of leather, in the form of a 

 breastplate, prepared so as tp be impenetrable by the thrust 

 of a bayonet, and explained the method of preparation. 



