VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. 25 



A further Account of the extraordinary Effects of the same Lightning at JVahe- 

 Jield. By Dr. Cookson. N° 437, p. 75. 



This storm of thunder and lightning happened the latter end of July, 1731, 

 and not only broke the glass and iron frames of the cross-chamber windows, 

 but at the same time split some studs in the corner of a wood-house, and 

 passing into a room, split likewise a large deal box, which stood in the south 

 corner of the room, where the lightning entered, and dispersed a great many 

 dozen of knives and forks, which were put up in the box, all over the room. 



On gathering up these knives and forks, some of them were melted, others 

 snapped in sunder; others had their hafts burnt; others their sheaths either 

 singed or burnt ; others not ; but what was most remarkable, on laying them 

 on a counter where there were iron nails, rings, &c. it was observed, that 

 when any of them were taken up, there hung a nail or ring at the end of each 

 of them; most of them were tried, and found to do the same. , 



Query. The polarity of the compass has been altered by lightning, as is 

 to be seen in the Philosophical Transactions: now how should lightning be 

 capable of communicating such a power in this case, since it is plain that it has 

 taken it away in another? 



The Description and Use of an Arithmetical Machine invented by Christian 

 Ludovicus Gersten, F. R. S. Professor of Mathematics at Giessen. N° 438, 

 P- 79- 



• Sir Samuel Morland was, it seems, the first who undertook to perforn) 

 arithmetical operations by wheel-work. To this end he invented two different 

 machines, one for addition and subtraction, the other for multiplication, which 

 he published in London, in the year l673, in 12mo. He gives no more than 

 the outward figure of the machines, and shows the method of working them. 

 The last for multiplication, is merely an application of the Napierian bones on 

 flat moveable disks; consequently his invention alone is not fit to perform justly 

 all arithmetical operations. 



After him the celebrated Baron de Leibnitz, the Marchese Poleni, and Mr. 

 Leupold, attempted to perform it after difi^erent methods. 



The first published his scheme in the year 1709, in the Miscellanea Beroli- 

 nensia; giving however only the outer figure of the machine. Signor Poleni 

 communicated his, but explaining at the same time its inner construction, in 

 his Miscellanea of the same year 1709. Mr. Leupold's machine, with those 

 of Mr. de Leibnitz and Signor Poleni, were inserted in his Theatrum Arith- 



VOL. VIII. E 



