SCIENCE, INVENTION, DISCOVERY. 



351 



was coiled, and was held in the left hand. The 

 spindle was a species of top, which was set in 

 motion by a twirl of the hand and by com- 

 bining its rotary motion with a gradual move- 

 ment away from the spinner. The size of the 

 fiber was equalized by passing it between the 

 finger and thumb of the right hand until 

 the motion of the spindle was exhausted, when 

 the thread was wound around it, and the process 

 was repeated. The improvement upon this 

 method by placing the spindle in a frame, and 

 making it revolve by mechanical action of the 

 hand or foot in connection with a wheel and 

 treadle, constituted the spinning wheel, which, 

 though probably in use long before, cannot be 

 traced farther back than A. D, 1530. The 

 spinning jenny, a machine of eight spindles, 

 was first invented in 1767, and subsequent to 

 that time many improvements in spinning I y 

 machinery have been made. 



Sponges and Sponge Fishing. 

 Sponges belong to the very lowest order of 

 animal life, and are attached like plants to 

 rocks, or similar substances. Those fit for 

 use are found generally in the seas of warm 

 climates. They consist of a framework, 

 which is sometimes of an elastic fibrous sub- 

 stance, and sometimes is made up of an aggre- 

 gation of hard, siliceous spicules. A sponge, 

 when fixed to a rock, increases in size by a 

 regular process of growth. To free them 

 from the jelly-like animal matter which they 

 contain when first brought, they are buried for 

 some days in the sand, and are then soaked 

 and washed. In the Turkish sponge fisheries 

 the sponge is obtained by diving, and the diver 

 guides himself beneath the water with a stone, 

 to which a cord from the boat is attached. 

 The best sponges are obtained from eight to 

 ten fathoms below the surface of the water. 

 In the Greek sponge fisheries of the Morea, 

 and on the Bahama Islands, a pronged fork at 

 the end of a long pole is used to detach the 

 sponges from the rocks below. Two species 

 are found in the Levant, another on the Ba- 

 hamas, and still another on the coasts of Flor- 

 ida and Mexico. 



Spontaneous Combustion may be 

 defined as the ignition of inflammable bodies 

 without the application of flame, or without 

 obvious cause of increase of temperature, and 

 arises from the well-understood liability of 

 certain bodies to undergo chemical changes 

 which develop sufficient heat to set them on fire. 

 Recently expressed fixed oils are particularly 

 disposed to oxidize when exposed to light and 

 air. They then absorb oxygen, and give out 

 carbonic acid and hydrogen. If the process 

 goes on rapidly, as it usually does when the 

 oil is diffused through light inflammable sub- 



stances, as cotton, tow, the waste used in 

 lubricating machinery, oatmeal, etc., the heat 

 may be sufficient to set them on fire. Bitu- 

 minous coal lying in large heaps is liable to 

 be ignited by the heat evolved in the decompo- 

 sition of the sulphuret. of iron which it com- 

 monly contains. The rapid absorption of water 

 by quicklime is also attended with development 

 of heat sufficient to ignite combustible bodies 

 in contact with the lime. Strong nitric acid 

 will act on straw, hay, and such bodies, so as 

 to render them spontaneously c Jinbustible. 



Stars, The. The idea at which astron- 

 omers have arrived respecting the stars, is, 

 that they are all of them suns, resembling our 

 own, but diminished to the appearance of mere 

 specks of light by the great distance at which 

 they are placed. As a necessary consequence 

 to this supposition, it may be presumed that 

 they are centers of light and heat to systems 

 of revolving planets, each of which may be 

 further presumed to be the theater of forms 

 of beings bearing some analogy to those which 

 exist upon earth. 



The stars seen by the naked eye on a clear 

 night are about two thousand in umber. 

 This, allowing a like number for the half of 

 the sky not seen, gives about four thousand, 

 in all, of visible stars. These are of different 

 degrees of brilliancy, probably in the main in 

 proportion to their respective distances from 

 our system, but also, perhaps, in some meas- 

 ure in proportion to their respective actual 

 sizes. Astronomers class the stars under dif- 

 ferent magnitudes, not with regard to appar- 

 ent size, for none of them present a meas- 

 urable disc, but with a regard to the various- 

 quantities of light flowing round them ; thus, 

 there are stars of the first magnitude, the 

 second magnitude, and so on. Only six or 

 seven varieties of magnitude are within our 

 natural vision ; but with the telescope vast 

 numbers of more distant stars are brought into 

 view ; and the magnitudes are now extended 

 by astronomers to at least sixteen. 



Steam Engines. The application of 

 steam as a moving power is claimed by va- 

 rious nations, but the first extensive employ- 

 ment of it, and most of the improvements 

 made upon the steam engine, the world indis- 

 putably owes to the English and the Americans. 

 It would appear that as early as 1543 a Span- 

 ish captain named Blasco de Garay showed in 

 the harbor of Barcelona a steamboat of his 

 own invention. It is most likely that Blasco 's 

 engine was on the principle of the ^Eolipile of 

 Hero, invented 130 B. C., in which steam pro- 

 duces rotatory motion by issuing from orifices, 

 as water does in Barker's mill. The preacher 

 Mathesius, in his sermon to miners in Nurem- 



