From Volume 56 of Philosophical Transactions of the Royal Society 1766


A letter from Michael Morris MD, member of the Royal College of Physicians in London and of the Royal Society, to Daniel Peter Layard MD, Physician to Her Royal Highness the Princess Dowager of Wales, Member of the Royal College of Physicians in London and of the Royal Societies of London and Gottingen, relating to experiments made upon the Somersham Water.

Dear Sir

From your very accurate account of the singular mineral water found at Somersham in Huntingdonshire and its salutary effects in many obstinate diseases, it appears to be highly deserving the attention of the public. I therefore agreed with pleasure to your proposal of repeating the experiments here, which you had formerly made at the Spring Head and in Huntingdon and adding such as you were obliged to omit in the country for want of proper apparatus.
As you intend to oblige the public with an account of the former, to which our repeated trials here were perfectly conformable, I shall confine myself in the following narrative, principally to the latter at which you assisted in my laboratory.

Experiments on the Somersham water
The water seemed clear in the bottles though there was some sediment at the bottom. It was clear and bright when poured into a glass but did not sparkle of emit air bubbles for a considerable time. It was austere and chalybeate to the taste.

Experiment I
On adding five grains of powdered galls to a glass of the water it soon became of a muddy blue, which in a little time turned light purple.
Several bottles of the water which had been kept upwards of two months exhibited the same appearance.
The water in some bottles which had been half emptied on purpose and corked slightly still preserved its property of striking a blue and purple with galls, though more faint.
From these experiments the Somersham water appears manifestly to have preserved its ferrunginous quality notwithstanding the long carriage from the Spring to London and to have lost very little of it for a considerable time after which renders it a valuable acquisition to the public as there are very few mineral waters generally known in England that do not lose their chalybeate properties in a few days and even at a small distance from their source which renders the importation of foreign chalybeate waters absolutely necessary at a considerable price.

Experiment II
Two pounds of the Somersham water were exposed to a gradual fire in a glass retort luted to a receiver.
The water as it grew warm became turbid and discharged air bubbles depositing at the same time an ochry sediment at the bottom. These appearances ceased before eight ounces were drawn off by distillation.
The distilled water proving on examination to be no wise different from common distilled water, the distillation was discontinued; the contents of the retort were poured into a white bason. On standing a night to settle, the liquor in the bason seemed to clear and a yellow sediment was seen at the bottom. The clear liquor was decanted into another bason.
The sediment carefully dried, weighed nearly four grains and proved to be chiefly ferrunginous.
The clear liquor was suffered to evaporate by the heat of the atmosphere in the month of August , pellicles were formed successively on the surface which breaking in a little time fell to the bottom; this continued until there remained about two ounces of liquor which was carefully poured from the pellicles into a cup and was set to evaporate in a moderate heat. The dried pellicles wighed 30 grains. They were insipid gritty and not soluble in water.

Experiment III
Six grains of the pellicles exposed to a strong fire in a covered crucible for three hours, became reddish when cold and lost a grain in weight but seemed not altered in other respects.

Experiment IV
Six grains of the same pellicles exposed on a test to a reverberatory heat for the same space of time; the vitriolic acid being volatised by the reverberated flame, was expelled from its terrene basis, so that the residuum when cold weighed but three grains, was acid to the taste, grew hot with water and communicated the same qualities to it that lime does. Hence the saline pellicles deposited by evaporation appear to be the selenites, or the vitriolic acid, united to a calcarious earth with a little iron.

Experiment V
The liquor in the cup being quite evaporated there remained some regular crystals standing in a whitish powder; the crystals weighed five grains and proved on examination to be regular crystals of alum.

Experiment VI
The whitish powder soon attracted moisture from the air and in the space of twenty four hours ran per deliquium into a brownish sub-acid austere liquor of a ferruginous and saline taste.
It appears from these experiments that the contents of the Somersham water are: First iron. Second Selenite. Thirdly alum. Fourthly from its taste and attracting the moisture of the air, some marine salt with a little alum and vitriol in the state of an aqua magistra aluminis & vitrioli incapable of crystallisation.
The Somersham water therefore seems to differ considerably from any of the mineral waters known in Great Britain or Ireland. For among the writers no one, except Dr. Short pretends to have separated crystals of alum from them and even he declares that in subsequent trials on the Nevil Holt water (from which he had once obtained some) he could not succeed.
Though if we consider the alum is composed of vitriolic acid united to an argillaceous earth, it will not be difficult to conceive that an acid water, passing through a stratumof such earth should act upon it and unite with a small portion of it, or that the water may dissolve some alum fin the stratum of decomposed pyrites where it is impregnated with iron and selenite. So that probably alum has been often overlooked in water wherein it existed, nor did we obtain any in our experiments until nearly all the selenite had been separated.
However as alum is a very powerful medicine; the quantity discovered in the Somersham water must have contributed not a little to its efficacy, in some of the remarkable cases wherein you have observed its success.

I am SIR

Your obliged humble servant

Michael Morris