VOL. XXXYI.] I'HILOSOPHICAL TRANSACTIONS. 375 



possible care. He found it frisking about a dead thistle growing in the field, 

 till a small motion cf the air made it skip to another place, and thence to 

 another, and another. 



It is now about 55 years since he saw this phenomenon, but he had as fresh 

 and perfect an idea of it, as if it was but of a few days. And as he took it 

 then, so he is of the same opinion now, that it was a fired vapour. 



The male glow-worms Mr. D. knows emit their shining light, as they fly; 

 by which means they discover and woo the females : but he never observed 

 them to fly together in so great numbers, as to make a light equal to an ignis 

 fatuus. And he was so near, that had it been the shining of glow-worms, he 

 must have seen it in little distinct spots of light; but it was one continuous 

 body of light. 



As to the communication from Italy, it is observed that tliese lights are 

 pretty common in all the territory of Bologna. In the plains they are very 

 frequently observed ; the country people call them cularsi, perhaps from some 

 fancied similitude to those birds, and because they consider them as birds, the 

 belly and other parts of which are resplendent like our shining flies. They 

 are most frequent in watery and morassy ground, and there are some such 

 places, where one may be almost sure of seeing them every night, if it be dark; 

 some of them giving as much light as a lighted torch, and some no larger 

 than tlie flame of a common candle. All of them have the same property in 

 resembling, both in colour and light, a flame strong enough to reflect a lustre 

 on neighbouring objects all around. They are continually in motion, but this 

 motion is various and uncertain. Sometimes they rise up, at others they sink. 

 Sometimes they disappear of a sudden, and appear again in an instant in some 

 other place. Commonly they keep hovering about 6 feet from the ground. 

 As they differ in size, so also in figure, spreading sometimes pretty wide, and 

 then again contracting themselves. Sometimes breaking to all appearance into 

 two, soon after meeting again into one body; sometimes floating like waves, 

 and letting drop some parts like sparks out of a fire. And in the very middle 

 of the winter, when the weather is very cold, and the ground covered with 

 snow, they are observed more frequently than in the hottest summer. Nor 

 does either rain or snow in anywise prevent or hinder their appearance; on the 

 contrary, they are more frequently observed, and cast a stronger light, in rainy 

 and wet weather. But since they do not receive any damage from wet weather; 

 and since, on the other hand, it has never been observed, that any thing was 

 set on fire by them, though they must needs in their moving to and fro, 

 meet with a good many combustible substances, it may from thence be in- 

 ferred, that they have some resemblance to that sort of phosphorus that shines 



