92 Mr Blackadder on a new 



faint appearance of a lunar rainbow. Wind W. ; Bar. 30.02. 

 26th. Very stormy; Bar. 29.17; wind S.W., boisterous; very 

 heavy rains. 



About 5 p. m. of the 14th December, a thunder storm was 

 experienced in many districts in Scotland, especially in Fife- 

 shire, where the lightning killed several cattle, and set fire to 

 some stacks of hay. 



In England, the same storm seems to have extended its ra- 

 vages very widely ; it was, perhaps, most severely felt about 

 Northampton, Leicester, and Doncaster. 



Here the pressure on that day was very low. At 9 a. m. 

 the barometer stood at 29.05, whence it descended to 28.75 in 

 the afternoon, and rose again a few tenths in the evening. 

 Winds variable, but chiefly east and west, very strong; mean 

 temperature 41°. I have the honour to be, Dear Sir, 



Very faithfully yours, 



Leith, 24^ April 1826. John Coldstream. 



Art. XVIII. — Description of a ?icw Register Thermometer, 

 without any Index; the principle being applicable to the 

 most delicate Mercurial Thermometers. By H. H. Black- 

 adder, Esq. F. R. S. E. * 



In the sixth Number of this Journal, we have laid before our 

 readers an account of Mr Blackadder's ingenious contrivance 

 for registering the indications of meteorological instruments 

 in the absence of the observer. In this contrivance, a sliding 

 index within the tube was indispensable, but, as this method 

 is liable to objections, particularly when great accuracy is re- 

 quisite, Mr Blackadder set himself to contrive the very inge- 

 nious method of registration which we are now to describe. 

 This register thermometer consists of two mercurial thermo- 

 meters, the tubes of which are attached to the same slip of 

 ivory, but having each a separate scale. 



One of the tubes a, Plate I, Fig. 2, is hermetically sealed 

 as usual, and the scale also is divided and numbered in the 



* This notice is an abstract of Mr Blackadilcr's paper, read before the 

 Royal Society on the 17th April last. 



1 



