MINERAL WATERS AND MEDICINAL SPRINGS OF ESSEX. 215
figures the "Tubulus marinus" and also one of the crystals of
the salt contained in the water.72a
Mr. Dalton suggests that the spring rose in the London
Clay containing marcasite (pyrites) and selenite.
(9).—The Colchester Spring.—The last of the small Mineral
Springs mentioned by Allen in 1699 was at Colchester. He
says it was at " the North End " of the town, but gives no
more detailed clue as to its exact locality. He classes it as
yielding a " Purging Water," and adds73 that it
" boyl'd meat without discolouring the flesh, which it rather whiten'd. The
water was much the same with Acton [Water], giving, with tincture of logwood,
a purplish red, a little tawny ; and, with gall, a clear yellow and pale ; but, in
half an hour, grew turbid, with a whitish cloud. But, with Lignum Nephriticum,
it became a little darkish, but clear, a little toward what spirit of vitriol does."
Mr. Dalton writes that the water came presumedly from the
London Clay slope on the north side of the Colne, with a trace
of the sulphates of magnesia and lime and possibly some
free sulphuric acid. The absence of iron is due probably to
complete peroxidation and consequent precipitation.
It will be convenient to notice, in the next place, an Essex
Spring—that at Woodford—which appears to have been first
brought into notice by the publication, in 1711, of Dr. Benjamin
Allen's second work, namely:—
(10).—The Woodford Wells.—Allen says74 of the water of this
spring that, "In the quantity of ten ounces and a half (within
a few grains), it weighed 29 grains more than common water,
after a dry year (1702)." He next details the results of his
various experiments upon the water, which he classes, like that
of the Upminster Spring, among "Waters containing a Salt
Alkalial, resembling Salt of Tartar, and the Sulphurous Salt of
Vegetables."
As to this spring in its palmy days, singularly little informa-
tion seems to be obtainable. Yet it certainly enjoyed, at one
time, a certain measure of fame. Morant, writing in 1768, says75
that "Woodford Wells were formerly in repute as purgative and
72a The "Tubulus marinus" appears to have been an example of Planorbis spirorbis
which had become encrusted with iron : the crystals are apparently those of selenite.
73 Chalybeat and Purging Waters, p. 128(1699). Apparently Allen does not mention it in
his second edition (1711).
74 Mineral Waters, pp. 19-30 (1711).
75 Hist. of Essex, i., p., 39 (1768).