Miscellanies. 



389 



the 25th May, 1812, in which 92 lives were lost. This is the greatest 

 destruction ever known from the same causes. In 1815, an explosion 

 occurred in a mine at Durham, in which 57 persons were destroyed, and 

 in another, 22 were killed in the same manner. The discoveries of Sir 

 Humphry Davy and other contributors to science and benefactors of 

 mankind have since rendered it certainly possible to avoid these destruc- 

 tive explosions. 



In our mines, no explosions of any extent has ever occurred from the 

 ignition of inflammable gas. Such events may as certainly be guarded 

 against as the bursting of steam boilers, the safeguards in each case being 

 as simple as effective. 



57. Relative temperature of the water of the Saco river, and the atmos- 

 phere for the years 1837 and 1838. — The table annexed gives the mean 

 temperature of the water of the Saco river, and of the air as observed at 

 Portland. — The fifth column shows what the temperature of the river 

 would be, provided it was subject to no other influences than those of the 

 atmosphere. — For example ; take the month of September ; — 54° air in 

 '37 : 63°.6 water in '37 : : 56° air in '38 : 65°.9 ; while the water by obser- 

 vation was 63°.2, — difference 2°.7. It will be observed that the differ- 

 ence in the mean temperature for the year is but yVo of a degree. 



I am aware that this is only an approximation to the truth, for in order 

 to insure perfect accuracy, the observations should be made throughout 

 the whole course of the river. J. M. Batchelder. 



58. British Association. — This interesting meeting convened on 

 the 26th of August at Birmingham. Prof. C. U. Shepard of this city 



