192 Dr. Stenhouse on some of the 



comes one of revolution, the cyclic cylinder itself degenerates 

 into two planes, analogous to two right lines, possessing re- 

 markable properties in the plane conies. 



These right lines, which correspond in the geometry of the 

 plane to the cyclic arcs of a spherical conic, were discussed in 

 the same paper from which the above theorems are extracted, 

 and were shown to be derivable from the foci of the reciprocal 

 conic by a polar transformation. 



Trinity College, Dublin, JoHN K. INGRAM. 



February 7, 1844. 



XXIX. On some of the Salts of Meconic and Komenic Acids. 

 By John Stenhouse, Ph.D.^ 



THE meconic acid employed in the following experiments 

 was made by Robiquet's process, as modified by Gre- 

 gory. The crystallized acid had only a slightly yellowish 

 shade, and when heated on platinum foil it disappeared with- 

 out leaving any residue When dried at 212^ F. it was sub- 

 jected to analysis. O'^SSS gram, of acid gave 0'696 of carbonic 

 acid and 0*084<7 of water. 



Calculated numbers. 



Per cent. 



Carbon . 42-45 Carbon . 14 = 42-460 



Hydrogen 2-07 Hydrogen 1 = 1-979 



Oxygen . 55-48 Oxygen .11= 56-5Q\ 



100-00 100-000 



Meconate of Lead. 

 When meconic acid is added in slight excess to a solution 

 of neutral acetate of lead, it causes a bulky flocculent precipi- 

 tate, which is nearly white, with only a slight shade of yellow. 

 The precipitate is insoluble in either hot or cold water. When 

 washed and dried at 212° F. it was subjected to analysis. 



I. 0-367 grm. of salt ignited with chromate of lead gave 

 0-215 of carbonic acid and 0-0211 of water. 



II. 0-554 grm. gave 0-331 of carbonic acid and 0-0346 of 

 water. 



* Communicated by the Chemical Society; having been read April 1, 

 1844. Dr. Stenhouse's paper On the Products of the Distillation of Me- 

 conic Acid, will be found in our preceding volume, p. 128. 



