TRANSACTIONS OF SECTION B. 973 
its sodium for the hydrogen of the latter while sodium methylate is reproduced, 
Methoxysuccinic acid procured by decomposition of its calcium salt with sulphuric 
acid is a crystalline solid melting at 101° to 103°C. Descriptions and analyses of 
the acid potassium salt and of the calcium and zine salts are given. The observed 
conversion of ethylic fumarate into methylic fumarate by the action of sodium 
methylate is by no means an isolated instance of the interchange of alcoholic 
radicles between an ethereal salt and an alcohol, but in the instances hitherto 
observed the interchange is accompanied by partial saponification, as when ethylic 
oxalate is converted by the action of potassium methylate into potassic methylic 
oxalate. The author finds that in this reaction normal methylic oxalate is also 
produced, and that in a similar manner ethylic cinnamate is converted into methylic 
cinnamate ; also, that if the ethylic salt is dissolved in methylic alcohol, the addition 
of certain salts, such as potassic carbonate, calcic chloride, and ignited borax, 
induces the interchange of alcoholic radicles. 
The general subject of the interchange of alcoholic radicles between ethereal 
salts and alcohols, induced by various reagents, is being now investigated. 
Action of sodium ethylate on ethylic fumarate,—This action has been previously 
described by the author, and ethoxysuccinic acid and several of its salts characterised, 
Further observations indicate that here also an intermediate sodium compound is 
formed, which, however, undergoes partial saponification, forming sodie ethylic 
ethoxysodosuccinate. 
Action of sodium methylate and of sodium ethylate on ethylic maleate——From 
the latter reaction no pure products could be obtained, but from the former a 
methoxysuccinic acid was procured, in its properties closely approximating to, if 
not identical with, the acid obtained from ethylic fumarate. 
Action of sodium methylate on hydric methylic maleate.—As it was found that a 
solution of maleic anhydride in methylic alcohol could be substituted for the 
normal maleic ether, this solution was used to obtain the material required for the 
further examination of the addition products from maleic acid. Hydric methylic 
maleate is formed by heating maleic anhydrid with methylic alcohol, and the sodic 
methylic maleate, formed on the addition of sodium methylate, being soluble in 
the alcohol, is quickly converted into sodic methylic ethoxysodosuccinate, which 
by saponification yields the sodium salt of a methoxysuccinic acid. The acid, 
obtained as before from the calcium salt, crystallises in the same manner and has 
the same melting-point as the corresponding acid obtained from fumaric acid. 
The salts also which have been already mentioned are identical, with the exception 
of the zinc salts, which seem to differ slightly. Both salts crystallise with four 
molecular proportions of water, three of which are given off at 100°, while the 
remaining molecule is retained to nearly the temperature at which the substance 
undergoes decomposition ; they appear, however, to differ in mode of crystallisation, 
and the salt derived from fumaric acid loses its last molecule of water of crystal- 
lisation at about 205° C., while that obtained from maleic acid does not become 
anhydrous till about 215° C. The high temperature required for the complete 
elimination of the water of crystallisation is remarkable, and an exact determination 
is attended with considerable difficulty, owing to the incipient decomposition of the 
salts at slightly higher temperatures. 
Action of sodium ethylate on hydric ethylic maleate.—By the addition of sodium 
ethylate to a solution of maleic anhydrid in ethylic alcohol, and subsequent saponi- 
fication of the product of the reaction, an ethoxysuccinic acid was obtained, the 
properties of which were found to be identical with those of the corresponding acid 
from fumaric ether. The calcium and barium salts were analysed and found to agree, 
as regards water of crystallisation and solubility, with the corresponding ethoxy- 
succinates previously obtained from fumaric ether. 
The above experiments show that fumaric and maleic acids yield alkyloxysuccinic 
aeids, which are identical with one another, or, if not identical, so closely resembling 
each other that their isomerism must be of the same nature as that of substances 
which differ only in optical and crystallographic characters. This supposition is by 
no means improbable in view of the fact that the malic acid prepared from fumaric 
acid by the action of caustic soda seems to differ from ordinary malic acid and 
