725 



order (n 2), and which the author considers to be also import- 

 ant in reference to the general theory of binary quantities : viz. if 

 YU=H(*](;ar,y,r) w ,DU=(Xd x +Yd y + Zd jr )U,andY,SY are what 

 U, DU become when (x, y, z) and (X, Y, Z) are interchanged ; then 

 the equation is of the form I . Y+ II . ilY + III . DU + IV . U=0. 

 Taking (x,y, z) as current coordinates and U=0 as the equation of 

 the curve, then if (X, Y, Z) are the coordinates of a point on the 

 curve, Y=0, and we have for the equation of the tangent at the 

 point in question iiY=0. The equation shows that the intersections 

 of the curve U=0 and the tangent IBY=0, lie on one or other of 

 the curves 111=0, DU=0, and that they do not lie on the curve 

 DU=0; consequently they lie on the curve 111=0, which is in 

 fact the before-mentioned curve of the order (n 2) . 



III. " On the Action of Acids on Glycol." By Dr. MAXWELL 

 SIMPSON. Communicated by Dr. FRANKLAND. Received 

 March 24, 1859. 



The glycol employed in the following research was prepared 

 according to Dr. Atkinson's excellent method *, to whom is due the 

 credit of having first substituted acetate of potash for acetate of 

 silver in its preparation. He was not the first, however, to prepare 

 it from bromide of ethylene, as M. Wurtz has been in the habit of 

 preparing it from that body for the last two years. 



The following slight modification of Dr. Atkinson's method will 

 be found very convenient, particularly when large quantities of gly- 

 col are to be prepared. Instead of heating the materials for form- 

 ing the monoacetate of glycol in a close vessel, they are heated in a 

 large balloon, connected with a Liebig's condenser in such a manner 

 as to cause the condensed vapours to flow back into the balloon. 



Action of Sulphuric Acid on Glycol Sulphoglycolate of Baryta. 

 Sulphuric acid forms an acid ether with glycol, which gives a 

 soluble salt with baryta. This compound is readily prepared by 

 exposing a mixture of equivalent quantities of glycol and sulphuric 

 acid (S 2 H 2 O 8 ) to the temperature of 150 Cent., diluting with water 

 and neutralizing with carbonate of baryta. This liquid, on being 

 * Philosophical Magazine, Dec. 1858. 



3 c 2 



