528 ^^ Correspondents. [November, 



TO CORRESPONDENTS. 



S. W. The gravelly matter you send us contains nothing of value 

 — the shining particles are mica. All is not gold that glitters. 



R. L. Gr. Instructions for grinding lenses can be found in Dick's 

 practical Astronomer. 



Dr. S. M. Mr. Rob't Clarke, Bookseller, on 6th St., Cincinnati, 

 will import for you any of the London Microscopes at §5.00, the 

 pound sterling, but by purchasing an American instrument you 

 save the duty of 40 per cent. 



Those who have not received their Feb. Number can now be 

 supplied by informing us per letter. 



SUMMARY OP METEOROLOGICAL OBSERVATIONS AT 

 FARMERS' COLLEGE, FOR AUGUST. 



Mean temperature of the month, 76.6 degrees, a little higher than 

 that of the same month last year. 



Mean temperature of warmest day the 8th, was 82.3; of the 

 coldest, the 30th, 67.8. 



The thermometer was the highest at 2 P. M. of the 8th, viz : 91.5; 

 the lowest on the morning of the 25th and 30th, viz : 60.6, making 

 its external range 31 degrees. The mean hight of barometer 

 was 29.127 being considerably higher than for the same month last 

 year, and yet we had just ten times more rain during the month, 

 than last year, showing that low barometer does not always bring 

 rain. Whole amount of rain during the month 4.060 inches. 

 SUMMARY FOR SEPTEMBER. 



Mean temperature, 65°, this is the same as last year. The max- 

 imum hight 40.5. The average hight of Barometer 29.200, a 

 remarkably high range. The amount of rain was .775 of an inch. 



There was some frost which did no damage, on the morning of 

 the 23d. and another a little harder on the morning of the 30th. 



