VOL. LXV.] PHILOSOPHICAL TRANSACTIOKS. 695 



Ex.— Let A B = 94''' 36' 58" 



BC = 23 28 5+ 



B = 2+ 5* 2-i Cotang. 0.3331770 



Dif. AB and BC = 7 1 8 3+ Sine 9.9760412 



Cosecant ab 0.0014080 



/M,= 26 3 44. Cot. 10.3166262 



JH Sin. »/* 9-286 



' Sin. BE 9.600 



Cot. AB 8.909 



Tang. Jb 9.344 



Sum = ^ = 4' 44" sine 7.139, this subtracted from /*, leaves the angle c = 25° 59' 0". 



This problem will be of use to find the right ascension of a star whose longi- 

 tude and latitude, and obliquity of the ecliptic are known, or to find the sun's 

 azimuth at any hour in a given latitude. 



XLVIl. Further Experiments and Observations in a Heated Room. By Charles 

 Blagden, M. D., F. R. S. p. 484. 



On the 3d of April, (says Dr. B.) nearly the same party as before,* together 

 with Lord Seaforth, Sir George Home, Mr. Dundas, and Dr. Nooth, went to 

 the heated room in which the experiments of the 23d of Jan. were made. Dr. 

 Fordyce had ordered the fire to be lighted the preceding day, and kept up all 

 night ; so that every thing contained in the room, and the walls themselves, 

 being already well warmed, we were able to push the heat to a much higher de- 

 gree than before. In the course of the day several different sets of experiments 

 were going on together ; but to avoid confusion, it will be necessary to relate 

 each series by itself, without regard to the order of time ; beginning with that 

 series which serves as a continuation of our former experiments. 



Soon after our arrival, a thermometer in the room rose above the boiling 

 point ; this heat we all bore perfectly well, and without any sensible alteration in 

 the temperature of our bodies. Many repeated trials, in successively higher 

 degrees of heat, gave still more remarkable proofs of our resisting power. The 

 last of these experiments was made about 8 o'clock in the evening, when the 

 heat was at the greatest : a very large thermometer, placed at a distance from 

 the door of the room, but nearer to the wall than to the cockle, and defended 

 from the immediate action of the cockle by a piece of paper hung before it, rose 

 1 or 2 degrees above 260° : another thermometer, which had been suspended 

 very near the door, stood some degrees above 240". At this time I went into 

 the room, with the addition to my common clothes, of a pair of thick worsted 

 stockings drawn over my shoes, and reaching some way above my knees ; I also 

 put on a pair of gloves, and held a cloth constantly between my face and the 

 cockle : all these precautions were necessary to guard against the scorching of 

 the red-hot iron. I remained 8 minutes in this situation, frequently walking 



» 



See the former experiments, p. 604, of this vol. of these Abridgements. 



