17li Food for Plants. 



At a deplli of forty-five feet under ground, the tem- 

 perature of the earth is uniform throughout the year. 



In summer time, the season oi" ripening moves north- 

 ward at the rate of about ten miles a day. 



The hmnan ear is so extremely sensitive that it can 

 hear a sound that lasts only the twenty-four thousandth 

 part of a second. Deaf persons have sometimes con- 

 versed together through rods of wood held between their 

 teeth, or held to their throat or breast. 



The ordinary pressure of the atmosphere on tlie sur- 

 face of the earth is two thousand one hundred and sixty 

 pounds to each square foot, or fifteen pounds to each 

 square inch ; equal to thirty perpendicular inches of mer- 

 cury, or thirty-four and a half feet of water. 



Sound travels at the rate of one thousand one hundred 

 and forty-two feet per second — about thirteen miles in 

 a minute. So that if we hear a clap of thunder half a 

 minute after the flash, we may calculate that the dis- 

 charge of electricity is six and a half miles off. 



Lightning can be seen bv reflection at the distance of 

 two hundred miles. 



The explosive force of closely confined gunpowder is 

 six and a half tons to the sc^uare inch. 



How to Preserve Eggs. 



To each pailful of water, add two pints of fresh 

 slaked lime and one pint of common salt ; mix well. Fill 

 your ban el half full with this fluid, put your eggs dowii 

 in it any time after June, and they will keep two years, 

 if desired. A solution of silicate of soda, commonly 

 known as water glass, is also used for the same purpose. 



Estimating- Measures 



A pint of water weighs nearly 1 pound, and is equal to 

 about 27 cubic inches, or a square box 3 inches long, 3 

 inches wide and 3 inches deep. 



A quart of water weighs nearly 2 pounds, and is equal 

 to a square box of about -4 by 4 inches and Si/o inches 

 deep. 



