374 VHILOSOHHICAL TRANSACTIONS. [aNNO 1729. 



able. But by pulling at h, the lever gf rises at f, and consequently draws up 

 the end b of the pall bd; which moving on the centre k, by its end d (by 

 means of the bar de) pulls down e, and raises a of the catch, so as to let the 

 rope run down; but to prevent its running too fast, one must pull a little 

 harder; then the semicircle loi will press against the wheel, and slacken 

 the descent of the weight; which will be wholly stopped by pulling still 

 harder: then the lever, pall, and catch will be in the position marked by. 

 pricked lines and small letters. Now if the person holding h, should care- 

 lessly let it go, the weight q in descending will bring down the pall at b, and 

 raise its other end, so as to throw the catch in again on the teeth of the 

 ratchet, and stop the whole motion without accidents. 



Fig. 6 represents the wheel and pinion at the other end of the axis, where 

 the same letters express the same parts. 



Fig. 7 represents the crane with the walking wheel, the whole turning round 

 on the strong post or puncheon s, which is fixed steadily upright by means of 

 the braces and cills llllllll; and when the wheel and pinion is used instead 

 of the walking wheel, all the other parts are the same, fp is a brace and ladder. 

 E, N, M, p, pulleys for the rope to run over, and come to the weight at h. 



Of the Meteor called the Ignis Fatuus,from observations made in England. By 

 the Rev. Mr. IV. Derham, F. R. S. and others in Italy, communicated by Sir 

 Thomas Dereham, Bart. F. R. S. N° 41 1, p. 204. 



It being the opinion of divers skilful naturalists, particlarly Mr. Fr. Willugh- 

 by and Mr. Ray, that the ignes fatui are only the shining of a great number of 

 the male glow-worms in England, or of the pyraustae in Italy, flying together, 

 Mr. D. consulted his friend, Sir Tho. Dereham, about the phenomenon, 

 being informed, that those ignes fatui are common in all the Italian parts. But 

 of the pyraustae, or fire-flies, he says, he never observed any such effects, 

 though there is an immense number of them in June and July. He also says, 

 that these pyraustae are called Liicciole, i. e. small lights, and that they are 

 not the farfalls, as Mr. Ray thought, which are butterflies. 



But Mr. D. has reason to think, that insects are not concerned in the ignes 

 fatui, from the following observations ; the first made by himself, and the 

 others received from Italy, by the favour of Sir Tho. Dereham. 



His own observation he made at a place in a valley between rocky hills, 

 which he suspected might contain minerals, in some boggy ground near the 

 bottom of those hills. Where, seeing one in a calm, dark night, with gentle 

 approaches, he got up within 2 or 3 yards of it, and viewed it with all 



