170 THE POPULAR SCIENCE MONTHLY. 



tion. (A good idea of such a precipitation is had by observing the 

 particles of water condensed from transparent vapor, in unusually high 

 thunder-heads, where the action is in some respects similar.) Between 

 these ascending columns are seen descending masses of cooler vapors, 

 rendered dark and smoky by relatively cool and opaque particles of 

 carbon, all or most of the other elements being still maintained by 

 the excessively high temperature in the condition of transparent va- 

 por. In the immediate region, however, where the cyclone is raging, 

 these bright ascending columns are drawn out horizontally by the in- 

 rushing metallic winds (which often reach a velocity of a thousand 

 miles per hour) into long filaments, pointing in general toward the 

 center of the disturbance, which is always occupied by a huge black 

 cloud of smoke (frequently twenty thousand miles in diameter) rap- 

 idly settling back into the interior of the sun. Over and across this 

 great central black cloud are often driven long arms of the shining 

 carbon-clouds, which, when the cyclonic action is very strong, bend 

 round into slowly changing spiral forms, very suggestive of intense 

 action. A striking illusion, invariably connected with this sight, is 

 that the observer seems to be viewing it from a position quite near 

 the scene of the disturbance, whose minute and complicated details 

 are seen with exquisite distinctness. 



After witnessing such a spectacle, the observer must have felt 

 great admiration for the men who have devised and successfully con- 

 structed an instrument capable of showing in action such enormously 

 energetic forces, the very existence of which would otherwise hardly 

 have been conceived. 



But, although the refracting telescope has now been brought to 

 such exquisite perfection, the first ones were exceedingly crude, and 

 it is interesting to trace the gradual development of the telescope 

 from a simple pair of spectacle-glasses, suitably placed one behind the 

 other, into the great refractors of Washington, Vienna, and Pulkowa, 

 which are monuments of optical and mechanical ingenuity. 



Spectacles were invented about the year 1300, but it was not until 

 1608 that a Dutch spectacle-maker, as a pretty experiment, combined 

 two such lenses in a way that made distant objects look nearer. A 

 rumor of this invention reached Galileo, at Venice, in 1609, and inter- 

 ested him so much that, before he had even seen one of them, he rea- 

 soned the problem out for himself, and in a few days produced a tele- 

 scope which made distant objects appear to be only one third as far 

 away as they actually were, by cementing a suitable spectacle-glass in 

 each end of a lead organ-pipe. With this instrument the astonished 

 senators of Venice derived great amusement in spying out ships at sea 

 from the top of the great bell-tower. 



So industriously did Galileo follow up his first achievement, that 

 soon he had constructed more than one hundred telescopes of various 

 sizes, one of which made objects look eight times nearer j and, finally, 



