THE INVENTOR OF THE LIGHTNING-ROD. 359 



his work had met in Berlin, but went on to construct his light- 

 ning-rod. After all that was necessary had been prepared, the 

 conductor was erected on the 15th of June, 1754, near the resi- 

 dence of the parson, for Divis, in order to avoid all risks, gave 

 up the idea of placing the lightning- 

 rod upon the building, but built it p~| 



separately in the free field near the rnJLri 



building. The lightning-rod of Divis *U™T"Lr 



was constructed as follows : j§| ||| 



A pointed, slender iron bar formed j^^li -^-^ 'li^ ^^ |l^f"H-i 

 the main part of the machine. Fas- ba"jj "^fl '» '— ' 



tened to it were two cross-bars, thus HI LZJ 



making four arms, across each of ^ n...jL_r ~U 



which, in turn, a shorter bar was laid. II 



And each of the twelve extremities so L_J 



w 

 effected bore a box filled with shav- 



„ . . -i.i. Fig. 2. — A Horizontal View of the 



mgs of iron m which twenty-seven Cross-bars. 



brass needles were stuck, making three 



hundred and twenty-four needles in all. The main bar was sup- 

 ported by a wooden column sufficiently high (forty-eight feet at 

 first, afterward one hundred and thirty-two feet) to secure protec- 

 tion for the building and its immediate surroundings. Several 

 iron chains connected the main bar with the earth. The effect of 

 the machine was to divide the lightning into as many sparks as 

 there were needles (three hundred and twenty-four), and thus to 

 lessen its force. It might, therefore, more properly be called a 

 lightning-divisor. 



Scarcely had the rod been erected when a storm came rushing 

 on from the north. Thunder-clouds hung over Prendice, and 

 occasionally white shafts of lightning were seen darting from the 

 clouds and flying toward the conductor. In a few minutes a 

 white cloud enveloped the machine, and the storm soon passed 

 away without doing any damage. For two years Divis continued 

 experimenting with his lightning-rod ; the results were published 

 by Dr. Scrinci in the Prague News (1754). Having satisfied him- 

 self in regard to the utility of his new machine, Divis offered to 

 the emperor a plan for erecting a number of conductors in vari- 

 ous parts of his empire. The emperor submitted the plan to 

 Viennese mathematicians, who were, unfortunately, a little be- 

 hind the times, and reported unfavorably upon the Bohemian's 

 proposition. The plan was consequently never carried out. Ab- 

 bot Marci, speaking about the report of the Viennese " connois- 

 seurs," says, in a letter to Divis, " Blasphemant, quae ignorant " 

 (They blaspheme that which they do not understand). And at 

 last, in 1756, Divis was compelled to remove his lightning-rod. 

 There had been a very dry summer that year, which the farmers 



