VOL. XXXVII.] PHILOSOPHICAL TRANSACTIONS. 44g 



less accurate, and difFeiently graduated from that which he had at this time, 

 he is apt to think, that the frost on Feb. 3, was altogether as intense, as that 

 on Dec. 30, 1708: for, though a frigorific mixture sunk the spirits but one 

 tenth lower in the old thermometer, and about 5 or 6 tenths in that he ob- 

 served with at this time; yet he takes the difference to be little, or none at all, 

 on account of the tenderness of the new above the old glass. 



And this degree of cold he takes to be as excessive as in any of the years 

 mentioned in the said Transaction; nay, any of the years when the Thames at 

 London was frozen over; and he is sure, colder than in 17 l6, when that river 

 was frozen over for several miles ; and booths and streets were made on the 

 ice, an ox roasted on it, &c. For, the lowest point of freezing in 17l6j was 

 on Jan. 7, when the spirits fell to 35 degrees only, in the thermometer he made 

 use of at this time: but the true cause of the freezing of the Thames that 

 year, was not barely the excess of the cold, but the long continuance of it; 

 which was also the chief cause of those remarkable congelations of that river 

 in 1 683 and 1/08, when Dr. Derham saw coaches driven over the ice, large 

 fires made on it, &c. 



Several Experiments concerning Electiiciiy . By Mr. Steplien Gray. 

 N°417, p. 81. 



In February l728-p, Mr. Gray repeated some of the experiments he had 

 formerly made, on the first discovery of an electrical attraction in several 

 bodies, not before known to have that property. He made several attempts on 

 the metals, to see whether they might not be made to attract by the same 

 method as other bodies were, viz. by heating, rubbing, and hammering; but 

 without any success: he then resolved to procure a large fiint-glass tube, to 

 see if he could make any further discovery with it, having recollected a suspi- 

 cion which he had some years before, namely, that as the tube, when rubbed 

 in the dark, communicated a light to bodies, whether it might not at the same 

 time communicate an electricity to them ; though he never hitherto tried the 

 experiment, not imagining the tube could have so considerable and surprising 

 an influence, as to cause them to attract with so much force, or that the attrac- 

 tion would be carried to such vast distances, as shall be found in the sequel of 

 this Transaction. 



Before he proceeds to the experiments, he gives a description of the tube: 

 it is 3 feet 5 inches in length, and near 1.2 inches in diameter: he gives the 

 mean dimensions; the tube being larger at each end than in the middle; the 



VOL. VII. 3 M 



