APPENDIX 



ADDITIONS AND CORRECTIONS FOR THE SECOND EDITION. 



A.— Page 81, ^18- 

 MECHANICAL POWER OF EVAPORATION. 



The mechanical power exerted by the air and the sun in hfting 

 water from the earth, in transporting it from one place to another, 

 and in letting it down again, is inconceivably great. The utilita-. 

 rian who compares the water-power that the Falls of Niao-ara 

 would afford if applied to machinery, is astonished at the number 

 of figures which are required to express its equivalent in horse- 

 power. Yet what is the horse-power of the Niagara, falhno- a few 

 steps, in comparison with the horse-power that is required to hft 

 up all the water that is discharged into the sea, not only by this 

 river, but by all the other rivers in the world, as high as the clouds. 

 The calculation has been made by engineers, and, according to it, 

 the force for making and Hfting vapor from each area of one acre 

 that is included on the surface of the earth, is equal to the power 

 of 30 horses ; and, for the whole area of the earth, it is 800 times 

 greater than all the water-power in nature. 



B.— Page 125, § 236. 

 THE MAELSTROM. 



The Maelstrom, that school-books make so much of, is a whirl- 

 pool, or rather an eddy, off the coast of Norway, supposed to be # 

 created by a conflict or meeting of the tides which have been di- 

 vided by the British Islands. 



C— Page 128, <§ 247. 

 QUANTITY OF SOLID MATTER IN THE SEA. 



It is difficult to form an adequate conception of the immense 

 quantities of solid matter, in solution, which the current from the 

 Atlantic carries into the Mediterranean. In the abstract log for 

 March 8th, 1855, Mr. William Grenville Temple, master of the 

 United States ship Levant, homeward bound, has described the 

 indraught there : 



*' Weather fine ; made 1^ pt. lee-way. At noon, stood in to Al- 



