278 I, Remsen on Parasulphobenzoic Acid. 
but according to the descriptions given it contains no water of 
crystallization. 
The analysis resulted as follows: 
04174 grams salt, dried over sulphuric acid, on being heated 
gradually to 190°, lost 0°0411 grams H?O; and then gave 0°2587 
grams BaSO4=—0'15212 grams Ba. 
Calculated. Found. 
C7H4805 200 53°62 
Ba 137. 36-73 36°44 
2H20 36 9°65 9°84 
373 100°0 
When Pee eee pure the length of the crystals is only depend- 
ent upon the depth of the liquid in which they are formed. It 
is more difficultly soluble, both in cold and in hot water, than 
the meta-salt. Like the meta-salt it does not give off its water 
of crystallization entirely below 200°; and it may be sub- 
jected to a much higher temperature without the danger of 
decomposition. : 
leium parasulphobenzoate is an amorphous powder which 1s 
somewhat more easily soluble in cold water than in hot, and 1s 
hence thrown down when a concentrated cold solution is boiled. 
en the potassium salts, obtained in the it ed ae of 
e solution 
salicylic acids is obtained, the salicylic acid forming in some 
cases fully half of the product. This fact taken alone led at 
first to the conclusion that the methyl groups of both the para- 
and ortho-sulpho acids had been oxidized ; and that thus not 
only parasulphobenzoic acid had been formed, but at the same 
time orthosulphobenzoic acid. Further investigation, however, 
showed conulasbvdly that this was not the case, but proved 
another interesting fact, of which I shall speak below. 
IV. Formation of Terephtalic Acid from Parasulphobenzote 
Acid. 
The recent experiments of V. Meyer*™ have tended to materi- 
ally modify the prevalent views in regard to the constitution 
* * Berliner Berichte, III Jahrgang, 112; and Annalen der Chemie u. Pharmacie, 
vi, 265. 
