SCIENCE, INVENTION, DISCOVERY. 



321 



Fire is said to have been first produced by 

 striking flints together. The poets supposed 

 that fire was stolen from heaven by Prome- 

 theus. Heraclitus, about596 B. C., maintained 

 that the world was created from fire, and 

 deemed it to be an omnipotent God ; lie taught 

 this theory about 500 B. ('. Zoroaster, king 

 of Bactria, was the founder of the sect of the 

 Magi, or worshipers of fire, still numerous in 

 the countries of the East, 2115 B. C. In the 

 Scriptures, God is said often to have appeared 

 in fire, or was encompassed by it, as in the 

 burning bush at Mt. Horeb. The wrath of 

 God is described as a consuming fire, and the 

 angels, as his ministers, are compared to it. 



Fire Engines, to force water, existed in 

 very ancient times. The first of the kind now 

 in use. but of a vastly inferior character, was 

 invented by two Dutchmen, each named Jan 

 Van der Heide, at Amsterdam, in 1518. In 

 1657, an improved engine was introduced at 

 Nuremberg by John Hantsch. Fire engines 

 were first known at Paris in 1699. The first 

 volunteer fire company in America was the 

 Union of Philadelphia, about 1736. 



Freezing, Fusing, and Boiling- Points. 



First Railroads. The first railroad ever 

 built for general traffic was the Stockton and 

 Darlington in England, which was thirty-five 

 miles long, constructed in 1825 by Edward 

 Pease and George Stephenson. In the same 

 year a railroad was projected in America by 

 Gridley Bryant, but it was not constructed until 



the following year, when Bryant secured the 

 assistance of Col. T. II. Perkins in the enter- 

 prise. This road was four miles long, and was 

 used for carrying granite from the quarries in 

 Quincy, Mass., to the site of the Bunker Hill 

 Monument. In 1827 the Mauch Chunk Rail- 

 way, a coal road, thirteen miles long, was 

 built, and February 27 of the same year the 

 Maryland Legislature granted a charter to the 

 Baltimore and Ohio road. The first locomo- 

 tive which proved of practical value was in- 

 vented by George Stephenson, the celebrated 

 English engineer, and was usect on the Stock- 

 ton and Darlington Railway. In 1829 a rail- 

 way line was built between Liverpool and 

 Manchester, of which Stephenson was the 

 principal engineer, and for this road he con- 

 structed the engine known as the Rocket, which 

 accomplished the till then undreamed-of speed 

 of thirty-five miles an hour. The first loco- 

 motive built in America was used on the Balti- 

 more and Ohio Railroad. 



Flies Walking on the Ceiling. For 

 a long time it was supposed that the ability of 

 the fly to walk on the ceiling was owing to 

 each of his feet being a miniature air-pump. 

 This, however, was proved to be fallacious, 

 and then a theory was propounded that it was 

 by means of a viscous substance exuded from 

 the hairs on its feet. Some eight years or 

 so ago this theory was thoroughly investigated 

 by Dr. Rombouts, who demonstrated that it 

 was only partly sound ; for, though the hairs 

 with which the foot-cushion is covered do cer- 

 tainly exude an oily liquid, the liquid is not 

 sticky, and does not harden when dry. Dr. 

 Rombouts proved by his experiments that the 

 true theory of the walking of flies on smooth 

 substances is that they hang on by the help of 

 capillary adhesion the molecular attraction 

 between solid and liquid bodies. By a series 

 of nice calculations, such as weighing hairs 

 and measuring their diameters, and sticking 

 the cut end of hair in oil or water to make it 

 adhere when touched to -glass, this scientist 

 proved that capillary attraction would uphold 

 a fly were it four ninths as heavy again as it is 

 at present. It is true that the foot-hairs are 

 very minute, but as each fly is said to be fur- 

 nished with 10,000 to 12,000 of these, we need 

 not be surprised at whattheycan do. Reason- 

 ing from this theory, we would conclude that 

 flies find it difficult to mount a glass slightly 

 dampened, because of the repulsion between 

 the watery surface and the oily liquid exuding 

 from the feet ; and they are likewise impeded 

 by a slight coating of dust, because the in- 

 terspaces between the hairs are filled with dust, 

 and observation seems to show this to be the 

 case. When we see a fly making his toilet, he 



