1818.] 



Scientific Intelligence. 



233 



Highest, April 6 

 Lowest, Dec. 18 



Weather. 



Fair 



Rain or Snow. . 



SE 



sw 



EVENING. 



30-61 I June 25 NW 



28-40 J Dec. 22 NW 



Days. 

 . 205 

 . 160 



365 



Wind. 



N and N E 



E and S E 



S and S W 



W and N W 116 



... 62° 



... 15° 



Times. 

 . 25 

 . 91 

 . 13S 



365 



No. 1. 



No. 2. 

 No. 3. 



Extreme Cold and Heat, by Six'* Thermometer. 



Coldest, December 23, Wind N W 15» 



Hottest, June 24, Wind S E. 16 



Wean temperature for 1817 46 75' 



Result of three Rain Gauges. In. 100 



Ou a conical detached hill above the level of the sea 600 feet 41-40 



Centre of the garden, 20 feet 31-01 



Kinfauns Castle, 129 feet 23-56 



Jlean of the three gauges 32-99 



X. Instrument for distinguishing the precious Stones. 



Dr. Brewster has lately constructed an instrument for distin- 

 guishing the precious stones from each other, and from artificial 

 imitations of them, even when they are set in such a manner that 

 no light can be transmitted through any of their surf aces. The 

 same instrument may be employed to distinguish all minerals that 

 have a small portion of their surface polished, either naturally or 

 artificially. The application of the instrument is so simple, that 

 any person, however ignorant, is capable of using it. We expect 

 soon to be able to give an account of it in this journal. 



XI. Mr. Stephenson's Latnps. 



Some experiments were lately performed at the Royal Institu- 

 tion with Mr. Stephenson's lamps, of which we believe the fol- 

 lowing to be a correct outline. 



There were four lamps employed of different forms ; those that 

 are designated in the report of Mr. Stephenson's Committee, by 

 the titles of first, second, and third, respectively; and a fourth, 

 which set ms to have been considered by them as not materially 

 differing from the third. The first, which is styled the tube and 

 -liflor lamp, consists, essentially, in a tube, which rises up within 

 B circular wick, to the lower orifice of which is adapted a move- 

 able valve, by which the aperture can be increased or diminished 

 at pleasure, and the rate of combustion of course proportionably 

 reduced. It was found, in several successive experiments, that 

 whenever the orifice of the tube was so far closed as to be barely 

 large enough to support the flame, yet it still always produced 

 explosion when exposed to the mixture of atmospherical air, and 

 hydro-carbortous gas. I be instrument employed in these expe- 

 riments was made by Mr. Hogg, of Newcastle. 



