InUdl'igence and Miscellanies. 365 



gles. The horizon of the pole being the equator itself, it is 

 a circle coinciding with that which represents the equator. 

 The horizon of the parallel of 45 degrees, being oblique to 

 the plane of projection, would be projected into an ellipse, 

 which would come nearer to a circle as the place to which 

 it belonged approached the pole, and nearer to a straight 

 line as the place approached the equator. The inventor has 

 adopted a very ingenious contrivance to represent truly all 

 these different positions of the horizon. The method how- 

 ever, cannot be rendered very intelligible without the aid of 

 a drawing, or without reference to the instrument itself. It 

 consists, substantially, of a small brass wire, coincident with 

 the equator when the horizon of the pole is represented, but 

 moveable southward for any other place, at the same time 

 being made by compression to assume an elliptical figure, 

 and thus including, in every situation, the part of the heavens 

 which is visible at each place respectively. We cordially re- 

 commend this little instrument to the attention of preceptors 

 of academies, who are not already furnished with a celestial 

 globe, and especially to private learners, who will find in it a 

 most useful guide and auxiliary ; and it is with the view of 

 rendering its construction and principles intelligible to such 

 of our readers as may procure it for their own use, that we 

 have been thus particular in our description of it. — O 



6. Of the precipitation of morphia from laudanum by am- 

 monia j also a spontaneous deposition of narcotin ; hij R. 

 Hark, M. D. Professor of Chemistry in the University of 

 Pennsylvania. — I believe it is not generally known that the 

 addition of ammoniated alcohol, to common laudanum, will 

 cause a crystalline precipitate of morphia in the course of a 

 few hours. If the precipitate thus obtained, be dissolved in 

 acetic acid, again precipitated by ammonia, and afterwards 

 collected and dried upon a filter, the morphia will be obtain- 

 ed nearly white, and may be rendered perfectly so, by repeat- 

 ing the solution by acetic acid, and precipitation by ammo- 

 nia. I have by these means obtained thirty grains of mor- 

 phia from an ounce of opium. 



Instead of alcohol impregnated with ammoniacal gas, a 

 mixture in equal parts of strong aqua ammonia and common 

 alcohol will answer. 



Narcotin is I find sometimes spontaneously precipitated in 

 a crystalline form from a solution of opium in proof spirit. 



