BORON AND FLUORINE. 9 



lacking. However, such borates are prepared only with difficulty 

 and as, in the present instance, the proportion of the components 

 and the conditions of formation were those corresponding to the 

 tetraborate with 10 molecules of water, it may safely be assumed 

 that the preparation was "pure" also from this point of view. 

 The final product was used in the experiments recorded in table 1. 



METHYL ALCOHOL. 



The methyl alcohol used in the quantitative elimination of 

 boric acid from borax should, of course, be anhydrous, or very 

 nearly so. It should also be as pure as possible, for it seems that 

 the smaller the amount of the usual impurities in the alcohol, 

 the more readily will methyl borate be formed with a mini- 

 mum expenditure of the reagent. The methyl alcohol for 

 the final determinations, therefore, was prepared by the saponi- 

 fication of methyl oxalate which admittedly yields a very pure 

 product. 



The methyl oxalate was made from dehydrated oxalic acid 

 and a good grade of almost anhydrous commercial methyl alcohol. 

 The mixture was heated in the water-bath for several hours under 

 a reflux condenser. It was then distilled from an all-glass appa- 

 ratus and the distillate collected as soon as it began to solidify 

 in the receiver. The product was drained and washed centrifu- 

 gally. Almost 2 kilograms of methyl oxalate were obtained in 

 this manner. It was melted on the water-bath and, after the 

 addition of some water, saponified by introducing small quanti- 

 ties of caustic soda solution through the upright condenser 

 until an excess of the alkali had been added. The resulting 

 mixture was boiled for several hours under the reflux condenser 

 and finally distilled. 



In testing the purity of the resulting aqueous methyl alcohol, 

 it was found that a neutral solution of silver nitrate produced a 

 slight white precipitate. The latter dissolved readily in dilute 

 nitric acid and did not consist of silver carbonate. The addition 

 of silver nitrate to extremely dilute solutions of ammonium 

 hydroxide and other soluble hydroxides gave similar precipitates, 

 which turned brown on boiling. The test seemed to indicate, 

 therefore, that the methyl alcohol was contaminated with a trace 

 of some volatile base, such as ammonia, and that the precipitate 



