THE FARMER AT HOME. 393 



by hand. It stretched out the threads as in common spinning of 

 carded cotton. Second, the water spinning frame, invented by Richard 

 Arkwright, in 1769. The essential and most important feature in this 

 invention, consists in the drawing out or elongating of the cotton, hy 

 causing it to pass between successive pairs of rollers, which revolve 

 with different velocities, and which act as substitutes for the finger and 

 thumb, as applied in common spinning. These rollers are combined 

 with the spindle and flyers of the common flax wheel. Third, the 

 mule. This was invented -by Samuel Crompton, in 1779. It com- 

 bines the principles of the two preceding inventions, and produces 

 finer yarn than that which is spun in either of the other machines. 

 It has now nearly superseded the jenny. Fourth, the power loom, 

 for weaving by water or steam power, which was introduced about the 

 end of the eighteenth century, and has received various modifications. 



The foregoing fundamental machines are used in the s'ame or 

 different establishments, and for different purposes. But, besides these, 

 various auxiliary machines are necessary to perform intermediate ope- 

 rations, and to prepare the material as it passes from one stage of the 

 manufacture to another. The number of these machines, and the 

 changes and improvements which have been made in their construction 

 from time to time, render it impossible to convey, in a work like the 

 present, any accurate idea of their formation in detail. 



SPONGE. A marine production, generally to be met with in the 

 shops in pieces only. Its texture is cavernous and porous. Its great 

 elasticity, and its property of imbibing, and as readily parting with, a 

 large quantity of water, render it useful. Sponge is to be chosen as 

 light as possible, perfectly clean, and free from stone, of as pale a color 

 as may be, with small holes, and fine, and soft to the touch. It grows 

 in the Archipelago, at considerable depths, on the rocks, about some 

 of the islands there ; and multitudes of people make a trade of diving 

 for it. It is also common in the Mediterranean and many other seas, 

 though in general browner or yellower, and not so fine as that of the 

 Archipelago. It adheres in large masses to rocks and stones, some- 

 times to large shells, and is either round, flat, or hollow, like a funnel 

 There has been much dispute among naturalists concerning the real 

 nature of the sponge ; nor is it yet satisfactorily decided whether it 

 belongs to the animal or vegetable kingdom. But it appears to be desti- 

 tute of irritability, as well as of any locomotive power ; and some recent 

 writers have maintained that it is during a part of its existence a vege- 

 table, and during the rest an animal. The opinion that sponge is, 

 like coral, the work of a polype, is erroneous. 



SPRINGS. In order to prove that the vapors raised by the heat 

 of the sun from the surface of the seas, lakes, and rivers, are abun- 

 dantly sufficient to supply the springs and rivers with fresh water, Dr. 

 Halley made the following experiment : he took a vessel of water, 

 made of the same degree of saltness with that of the sea, by means 

 17* 



