Minutes of Meetings. 379 



is to be conceived to' represent an orthographic projection of the celestial 

 sphere on the plane of the meridian. Let the straight line, e e, be the 

 projection of the equator. 



Set off the arcs e h = E H' = the co-latitude of the place of observa- 

 tion ; then will H H' be the projection of the horizon of that place. 

 From the equator set off the two arcs E d = the declination of the star, 

 and draw the straight line, d d, which will be the projection of the 

 parallel of declination. From the horizon set off the arcs h A = h' a = 

 the altitude of the star, and draw the straight line A A, which will be the 

 projection of the parallel of altitude. Then s, where A A intersects D D, 

 will be the orthographic projection of the star. 



Round o, with the radius o c = ^ A a, describe a circle, or part of a 

 circle. From s let fall s b perpendicular to the horizon h o h', and pro- 

 duce this perpendicular till it cuts the last mentioned circle. Let c be 

 the point of intersection. Draw the straight line o C, and produce it till 

 it cuts the graduated circle in f. Then will the arc H' F be the azimuth 

 of the star, measured from that pole which is above the horizon. 



This method answers best when the star observed is at a distance 

 from the meridian without, being so near the horizon as to be much 

 affected by refraction, or so near the zenith as to make its azimuth 

 uncertain. 



A geometrical construction analogous to this has been used by the 

 author to determine the apparent solar time from an observation of the 

 sun's altitude. 



Professor Gordon gave " An Account of New Formulas for Calculating 

 the Strength of Pillars of Cast and Wrought Iron." 

 Mr. Ure exhibited a Lamp of a new construction. 



February 7, 1855. — The Pbesibent in the Chair. 



The following were elected members : — Mr. James Ferguson, Mining 

 Engineer, Gas-Coal Works, Lesmahagow ; Mr. James M'Intosh, Taimer, 

 129 Stockwell Street; Mr. Daniel Macnee, Painter, 132 West Regent 

 Street ; Mr. Wm. Robertson, C. and M.E., 97 Union Street. 



On the recommendation of the Council, the Society agreed to grant 

 a sum not exceeding £6 for the purchase of a new Black Board. The 

 first vote was taken, and the motion was carried unanimously. 



Mr. Bryce read "Notices of the Natural and Civil History of the 

 Crimea — its Geology and Climate." 



