Intelligence and Miscellaneous Articles. 75 



Playfair, who first mentioned it, gives its melting-point at 120° F., 

 whilst it really fuses at 129° F. When cold, it is exactly like palmitic 

 acid, appearing in scaly crystals. It is however more readily soluble 

 in alcohol, and crystallizes from this solution in laminae of a pearly 

 lustre. Analyses of the acid itself, as well as of its silver, lead, cop- 

 per, baryta and magnesia salts, furnish concordant results leading to 

 the formula C- 8 H 47 3 + RO. Its combination with oxide of sethyle 

 (myristic aether) melts at 83 0, 3 F., crystallizes very beautifully in 

 the cold, and dissolves readily in hot alcohol. Its composition is 

 C«H«Os-|-C*H s O. 



Laurostearic acid, which was prepared by Marsson from the oil 

 of laurel berries, by Sthamer from the fat of pichurine beans, and 

 by Gorgey from cocoa-nut oil, melts with rather more difficulty than 

 stated by these chemists. Its melting-point is 110 o, 5 F. It dissolves 

 very readily in alcohol, and only crystallizes partially from this solu- 

 tion at a low temperature. It is transparent, but still forms scaly 

 crystals; it consists of C- 4 H 23 3 + HO, as appears from analyses 

 not only of the acid itself, but also of its silver, lead and baryta 

 salts. 



Gottlieb has already noticed, that stearic acid mixed with mar- 

 garic acid in certain proportions, may acquire a lower melting- 

 point than that of the last-mentioned acid. As this, according to 

 the author's previous investigations, is a mixture of stearic and 

 palmitic acids, this peculiarity must be a property of this mixture, 

 which in fact is the case, as niargaric acid itself is nothing but a 

 mixture of palmitic acid with stearic acid, which melts more readily 

 than the former acid. Heintz has found, however, that any two 

 fatty acids may form a mixture possessing a lower melting-point than 

 even the most fusible of them in a pure state. He has drawn up 

 the following tables, showing the melting-point and mode of solidi- 

 fication of mixtures in simple proportions of every two of the four 

 acids, — stearic acid, palmitic acid, myristic acid, and laurostearic 

 acid : — 



A mixture of 



stearic palmitic 



acid. acid. Melts Solidifies 



parts. parts. at at Form of solidification. 



100 1 56-56° F. .. °F. scaly crystalline. 



90 10 152-96 114-5 the same. 



80 20 14-9-48 140-54 finely acicular. 



70 30 145-08 106-68 the same. 



60 40 140-48 133*70 uncrystallinetubercular. 



50 50 133-88 131-00 laminar crystalline. 



40 60 133-40 130-1 the same. 



35 65 132-08 1 2974 uncrystalline, shining. 



32-5 67-5 131-36 129-2 the same. 



30 70 131-18 129'2 the same, lustreless. 



20 80 135-5 128-81 very indistinctly acicular 



10 90 140-18 130-1 beautifully acicular. 



100 143*6 .. scaly crystalline. 



