66 
THE CHIGWELL ROW MEDICINAL SPRINGS. 
then left off [digging] and, in one night’s time, I suppose there 
might be 6 or 8 Hhds. of water in the well. It had a steely and, 
at the same time, a saline tast ; a thick scum on the top, re¬ 
flecting various colours ; and its smell [was] volatile and 
sulphureous. 18 
The Reader may now, perhaps, expect the natural history 
of waters, their origin, the cause of springs, the nature of all 
mineral waters, with their analysis, specific gravities, etc., 
etc. ; but, as these matters would lead me far beyond the bounds 
of a pamphlet, I hope I shall be excused from entering upon a 
work that would fill a folio. However, the subject naturally 
leads me to say something of water in general, which will give 
some information to the reader and which he may compare and 
contrast w th such as are render’d medicinal—i.e., by being 
mixed w th metalline and fossil substances. . . . 
[The writer then discourses at length on various kinds of 
waters—Rain water, Spring water. River water, Pump water. 
Pond or Stagnant water, and so on. He next proceeds to set 
forth (with what was certainly, for those days, considerable 
chemical knowledge) the various tests by means of which the 
purity of waters and their mineral or saline constituents are 
ascertained. He concludes :—] 
Chigwell row water, by the addition of [Aleppo] galls, turns 
black ; with urinous salt, greenish ; with lime water, turbid 
and bluish ; [and], with Sal Saturni, milky. This water, by 
being exposed in an open bottle, drops its ocrey sediment and 
with it a great deal of its power of tinging with galls. In about 
12 hours time, by exhaling of three 4ths. away, the remaining 
part shot into a figured salt, which tasted bitterish and astringent. 
“ mass, but often segregated into nodules or impregnating fossil wood. The ‘particles ’ 
“ are most probably crystals of selenite (sulphate of lime), formed by the oxidation of the 
“pyrites into sulphate of iron and by the action of this on carbonate of lime, either native 
“to the clay or derived by the infiltration from the overlying Boulder-Clay. Lower down, 
“ the diggers found the soil becoming ‘more yellowish and okery.' They had rome upon 
“ one of the sandy bands in the upper portion of the London Clay (indicating the 
“ approaching change into the Bagshot Sands), and this brought in from its outcrop a feeble 
“ supply of water, the oxygen dissolved in which first helps to form the sulphate of iron, 
“ as mentioned, and then to break up some of it or of the carbonate into ochreous peroxide, 
“leaving the rest in solution, with o»her salts unaltered.’ 
18 Mr. Dalton writes :—“ The term volatile, as applied to smell, may imply pungency, but 
“more probably means evanescent, the smell disappearing on the escape of the sulphuretted 
“ hydrogen, which is generally oresent in such chalybeate waters. The taste would be due 
“ predominantly to carbonate of iron, partly to the sulphate, and partly to the Epsom salts 
“ (sulphate of magnesia', which is largely present in many Essex waters. Some sulphate of 
“alumina may also occur. The iridescent colours are due to the formation of a film of 
“ insoluble peroxide of iron in contact with the air.” 
