Dr. Redtenbacher on a Class of Organic Acids. 507 



proate of baryta and the foregoing fine granular crystals of 

 caprylate of baryta, there appeared crystals in large plates, 

 with a mother-of-pearl lustre, which recrystallized several 

 times in the same form. It appeared from analogy that it 

 could only contain an acid whose composition was between 

 the caproic and caprylic acids, or it rather was presumed to 

 be with certainty the cenanthylic acid discovered by Tilley. 

 The quantity of the salt obtained was very small, Only a few 

 grammes, nevertheless it was necessary to recrystallize it in 

 order to take only the middle portions. I obtained only about 

 400 milligrammes of the pure salt for examination, of which 

 a part was used for qualitative analysis. The properties how- 

 ever agreed in every respect with the cenanthylate of baryta 

 of Tilley. There remained only sufficient for the determina- 

 tion of the atomic weight of the salt. 



0*3273 grm. cenanthylate of baryta gave 0*162 grm. car- 

 bonate of baryta ; this gave cenanthylate of baryta : — 



Calculated. Found. 



Atomic weight ..... 2469 2489 



Anhydrous acid . . . . 1413 1413 



In 100 parts,— Baryta . * 38*73 38*45 



7. Caprylic Acid. — The before-mentioned very small fine 

 granular crystals from cenanthylate of baryta were decom- 

 posed by sulphuric acid ; they gave out the odour of sweat, 

 and formed the known properties of caprylic acid. I have 

 obtained crystals of caprylate of baryta in other forms. I 

 left a cold saturated solution of this salt for eight months 

 in a glass vessel covered with blotting-paper to spontaneous 

 evaporation. During this time the solution had evaporated 

 to three-quarters of its former bulk, and at the bottom were 

 deposited prismatic crystals, above one-quarter of an inch in 

 length, very hard, with a waxy lustre. The atomic weight 

 showed me that they were pure caprylate of baryta. 



Of the above fine granular crystals, 0*493 grm. gave 0*229 

 grm. carbonate of baryta ; 0*3265 grm. gave 0*545 grm. car- 

 bonic acid and 0*212 grm. Mater. 



Calculated. 

 16 eqs. Carbon .... 1200*0 

 15 ... Hydrogen . . . 187*5 



3 ... Oxygen .... 300*0 



7 ... Baryta .... 956*9 



1 ... Caprylate of baryta 2644*4 100*00 100*00 



8. Pelargonic Acid. — Between capric and caprvlic acids no 



2M2 



