524 PHILOSOPHICAL TRANSACTIONS. [aNNO 1741. 



found 25 feet of water, of a sulphureous smell and taste, which went ofF, after 

 the well had been opened some days. As he had a strong suspicion, that this 

 water was impregnated with some mineral, he examined it by the following 

 experiments : 



1. It curdled milk. — 2. It became green, when mixed with syrup of violets, 

 which colour disappeared in a few days. — 3. Being poured on green tea, it did 

 not acquire any colour. — 4. Being mixed with powdered galls, it acquired a 

 deeper brown colour than rain-water did, and continued turbid ; whereas the 

 rain-water continued clear, after the galls were subsided. — 5. Being shaken in a 

 close-stopped phial, it disploded a vapour on opening the phial before the com- 

 motion ceased, with a more audible noise than common water did. — 6. Being 

 mixed with oil of vitriol, and oil of tartar, a much more considerable ebullition 

 was raised, than by the mixture of those liquors with rain-water. — 7, Six quarts 

 of this water, being boiled to a pint, let fall a large quantity of a fine, whitish, 

 insipid powder; and the water so boiled had a very strong saline taste, with a 

 mixture of bitterness, not unlike the sal cartharticum amarum. — 8. It let fall a 

 copious white sediment, on the addition of the oil of tartar, which has the 

 same effect on a solution of alum, or of sal cartharticum amarum. — 9. The 

 boiled water, after it had deposited its earth, precipitated large white flakes, on 

 the addition of oil of tartar. — 10. It differs from a solution of common salt. 

 For the oil of tartar, being dropped into that solution, caused only a slight pre- 

 cipitation, which was soon afterwards absorbed again by the water. — II. It does 

 not lather with soap. 



Having made these experiments, Mr. M. was satisfied, that this new spring 

 was really a purging water, as it was afterwards found by experience. Several 

 persons tried it, to their great advantage. Being drank fresh, in the quantity 

 of 5 half pint glasses, it purges quickly, not sinking, but raising the spirits. It 

 is found to be very diuretic. 



These properties of the Dulwich water do not seem to be owing to any of the 

 materials found in digging the well. The pyritse are known to be a mixture of 

 iron and sulphur ; but this water seems to have hardly any parts of iron in it 

 [Exp. 3 and 4.] The spirit, with which it abounds, [Exp. 3 and 6] may, per- 

 haps, be owing to a fermentation of the sulphur, which is continually flying 

 off, as appears by its strong smell, after it has been for some time covered up. 

 And a silver cup, which has been often used in drinking this water, has acquired 

 a yellowish colour. 



The ludus helmontii affords nothing but iron. Nor does the clay, through 

 which they dug, discover any salt in its composition. We may therefore con- 

 clude, that the hill, which lies between the old wells and this new one, con- 

 tains the purging salt, with which these waters are impregnated. 



