4 THE POPULAR SCIENCE MONTHLY. 



anger of the gods. The barbarians laughed at the threat. He then 

 constructed a dragon of the most volatile paper, and in this inclosed a 

 mixture of sulphur, pitch, and wax, and so artistically arranged all his 

 materials that when ignited it would illumine the machine and exhibit 

 this legend — ' The wrath of GocV The body being formed and the in- 

 gredients prepared, he affixed a long tail, and committed the machine 

 to the heavens. Favored by the wind, it soared aloft toward the 

 clouds. The spectacle was terrific. The barbarians beholding it were 

 smitten with the greatest astonishment and fear. . . . Thereupon with- 

 out delay," says Kircher, " they threw open the gates and suffered the 

 prisoners to go forth in peace." 



In the middle ages, anybody at all distinguished by knowledge of 

 science was credited with the art of flying, and indeed in many cases 

 did not scruple to claim it. Albertus Magnus was one of these, but 

 refused to give particulars to the world at large. He tells us, however, 

 how to make thunder. Says he : " Take one pound of sulphur, two 

 pounds of willow carbon, and six pounds of rock-salt, ground very fine 

 in a marble mortar ; place where you please in a covering made of fly- 

 ing-papyrus to produce thunder. The covering, in order to ascend and 

 float away, should be long, graceful, and well filled with this powder ; 

 but to produce thunder the covering should be short and thick, and 

 half full." 



Roger Bacon, an eminent philosopher of the thirteenth century, also 

 claimed to have knowledge of the art of flying, but believed also in the 

 wisdom of silence concerning the details. But in his writings we find 

 flashes of real light. He speaks of the possibility of constructing en- 

 gines of great power to traverse land and sea ; and seems to have been 

 the first to have tolerably clear ideas of the principles involved in the 

 construction of balloons. He describes a large hollow globe of copper 

 or other suitable metal wrought extremely thin. It must then, he says, 

 " be filled with ethereal air or liquid fire, and then be launched from 

 some elevated point into the atmosphere, where it will float like a ves- 

 sel on the water." 



In his day the air was supposed to have a well-defined upper limit, 

 like the water. 



Friar Bacon too has been credited with the invention of gunpow- 

 der. He was of course accused of holding communion with the devil. 

 Good Pope Nicholas placed his writings under a ban, and his wings 

 were effectually clipped. 



Shortly after his time, the project of training up children from 

 infancy to fly received a good deal of attention, and, if we can trust 

 the accounts, considerable progress was made, for it is said that, by 

 combined running and flying, individuals could skim over the ground 

 with great rapidity. 



Regiomontanus, a famous mathematician, is said like Archytas to 

 have formed an artificial dove, which flew out to meet the Emperor 



