On the Rate of Increase of Underground Temperatures. 459 



Mr. Boot has continued his observations in the bore which he 

 is making at Swinderby, near Scarle (Lincoln). It has now- 

 been carried to the depth of 2,000 feet, and is in earthy lime- 

 stone or calcareous shale, of Carboniferous age. Its diameter in 

 the low 

 78° F., 



• part is only 3| inches. In April last the t 



was observed at 2,000 feet; the water, in each case, having been 



»ed for a month. Supposing these results not to be 



vitiated bv convection, and assuming the mean temperature at 



e to be 50°, we have an increase of 29° in 2,000 feet, 



which is at the rate of 1° in 69 feet. 



Mr. Symons has taken a series of observations at the depth 

 of 1,000'feet in the Kentish Town well, with the view of deter- 

 mining whether the temperature changes. m ' 

 employed is a very large and delicate Phillips' maximi 

 mometer. The following is a list of the observations :- 



i rlier- 



— - 



ln a. 



■sfr 



Meo( 



4$. 



Temperature. 



,; May 8 



1000 



6450 



May 8 

 July 2 



1007 

 1009 



66-82 



" July 2 



1000 











« July 28 







Sept. 8 







" Sept. 8 

















Oct. 30 













Dec. 3 







" Dec. 3 



1000 



63-80 



Jan. 7 



1009 











Feb. 1 













March 3 



1005 









6390 



May 3 



1006 





;; Jg* J 



1000 



Soo 



Ju?y 7 



1005 



6758 



" July 7 



:: H, ,! 



" Oct. 2 

 " Nov. 1 











1000 

 1000 



6387 



Sept. 10 

 Oct. 2 

 Oct. 19 

 Nov. 1 

 Dec. 1 



1003 

 1005 



67-58 

 broke. 



•h the *tx*« i 



raised and lowered, as ,1,. •, il ■ d. v. ith a diagram, in the Keport 

 for 1869. The above table shows that there is al* 



in the interval between lowering 

 the therm t again, Recent o bs Rations by 



means of a fixed mark on the wire, have shown that the change 

 is not, in the main, a «, but an alternation 



of length. It is probably due in part to the greater 

 Which the ring than in lowenng, a cxrc urn- 



stance which will cause a temporary difference of lengtn vana- 



