vol,. XXIII.] PHILOSOPHICAL TRANSACTIONS. 17 



down a great oak-tree or two, frightened the weeders out of the field, and made 

 others lie down fiat on their bellies, to avoid being whirled about and killed, as 

 they saw had happened to several jackdaws, which were suddenly snatched up, 

 carried out of sight, and then thrown a great way off among the corn ; at 

 length it passed over the town of Hatfield, to the great terror of the inhabitants 

 filling the whole air with the thatch it took of from some of the houses ; then 

 touching on a corner of the church, it tore up several sheets of lead, and rolled 

 them together in a strange manner; soon after which, it dissolved and vanished, 

 without doing any further mischief. 



There was nothing more extraordinary in this, than in the other that I gave an 

 account of in N° 281 ; and by all the observations that I could make of both, 

 I found that had they been at sea, and joined to its surface, they would have 

 carried a vast quantity of water up into the clouds, and the tubes would then 

 have become much more strong and opaque than they were, and have continued 

 much longer. 



It is commonly said that at sea, the water collects and bubbles up a foot or 

 two high under these spouts, before they are joined : but this is a mistake owing 

 to the pellucidity and fineness of those tubes, which certainly touch the surface 

 of the sea before any considerable motion can be produced in it, and that when 

 the pipe begins to fill with water, it then becomes opaque and visible. As for 

 the reason of their dissolving of themselves, after they have drawn up a great 

 quantity of water, I suppose it is by and through the great quantity of the water 

 they have carried up, which must needs thicken the clouds, impede their mo- 

 tion, and by that means dissolve the tubeSc 



On the Tangents of Curves , deduced immediately from the theory of Maxima and 

 Minima : with the Theorem, by ivhich, with the Help of the same Calculusy 

 certain Properties relating to the Conic Sections are investigated. By Mr. 

 Humphry Ditton.* N° 284, p. 1333. Translated from the Latin. 



I here propose a method of tangents, which is easy and sufficiently general, 

 indeed quite general, as serving, by the same operation, for all curves whatever. 



* Mr. Ditton was a very sound and respectable mathematician, as well as divine, and published 

 many useful works on both these subjects, though he died but a young man, viz. Anno 1715, in the 

 40th year of his age. He was born at Salisbury, was bred among the dissenters, and in compliance 

 with the desires of his father, against his own inclination, officiated for some time as minister to a 

 congregation. But on his father's death he pursued his favourite subject, the mathematics, and 

 through the interest of Sir Isaac Newton he became master of the new mathematical school in 

 Christ's Hospital, London. 



Besides the present, he has another paper in the Philos. Trans, for 1705>,¥iz. on spherical catojp- 



VOL. V. D 



