On evaporating a portion of the alcohol from the material left after titrating with the sodium hydroxide, and adding water to obtain an aqueous solution of the sodium salt, an emulsion was formed, and on standing globules of the free resinous acid separated. From the data thus obtained, it can readily be seen that the acid or acids which constitute the BARIUM ACID must have a number of carboxyl groups and form a different series of salts by precipitation than by direct titration. The salt or salts formed by direct titration, although neutral to phenolthalein may be acid in structure. This is further shown by the fact that the potassium salts produced by direct titration are readily hydrolyzed. The acid number obtained by the precipitation of the barium salt may be called the COMBINING VALUE, and the acid number obtained by titration the TITRATION VALUE. A number of molecular weight determinations were made on the free barium acid. McCoy’s Boiling Point Apparatus was used and Merk’s benzol (free from thiophene) was used as the solvent. A weighing pipette with a bulb was used to introduce the material, the bulb being weighed before the material was introduced into the apparatus, and afterwards, the difference being the weight of the material used. Wt. of pipette (before) 16.3670 14.8895 Wt. of pipette (after) 14.8895 12.4610 Wt. of material used 1.5225 2.4285 Original temperature 3.53 3.53 Final temperature 3.60 3.62-3 Change in temperature .07 .09 Volume of solution 37 cc 43.5 cc Constant for solvent 3280 3280 Approx. Molecular Wt. 2000 2100 or 1800 Combustions were made using the barium acids. By qualitative tests it was found that the acids contained only carbon, hydrogen and oxygen. The following gives the results of the combustions. Wt. of boat 2.8402 2.8402 Wt. of boat and resin 3.0500 3.0250 Wt. of resin .2098 .1848 Wt. of H2SO4 tube 78.0250 78.1415 Wt. of tube plus water 78.1520 78.2550 Wt. of water .1270 .1135 Hydrogen equiv. .0143 .0126 Wt. of KOH bulb 48.8140 51.7095 Wt. of bulb plus CO2 49.3800 52.2085 Wt. of CO2 .5660 .4990 Carbon equiv. .1543 .1361 Percent Hydrogen 78.5% 73.6% Percent Carbon 6.8% 6.8% Percent Oxygen 19.7% 19.6%