PART III.

Of Dr. NoOTH's Objections to the preceding Method of impregnating Water with fixed Air, and a Comparison of it with his own Method, both as published by himself, and as improved by Mr. PARKER.

I can easily forgive Dr. Nooth for his reprefenting me as having no other merit than the first publication of the method for impregnating water with fixed air, accounting for it as I have done before; but I cannot fo eafily forgive another paragraph in his paper, the tendency of which is intirely to difcredit a method, which, though it is, in fome respects, inferior to his own, has nevertheless its peculiar advantages and every advantage cannot poffibly concur in any one method. He fays, P. 59, "Independent of the inconveniencies

attending the procefs, there was another ob66 jection to the apparatus, which, with moft "people, might have confiderable weight. "The bladder, which formed part of it, was "thought to render the water offenfive; and "when the folvent power of fixed air is confidered, it will not appear improbable, that "the

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"the water would be always more or lefs "tainted by the bladder. In fome trials which "I made with Dr. Prieftley's apparatus, it

always happened that the water acquired an urinous flavour; and this tafte was, in ge"neral, fo predominant, that it could not be "fwallowed without fome degree of reluctance."

That Dr. Nooth did produce an impregnated water which he could not fwallow without reluctance, and even that, in the trials to which he refers, he generally produced fuch water, I am far from doubting; because that might happen from various causes. But that the urinous flavour came from the bladder, as fuch, I will venture to fay is not poffible. For then it would always have had the fame effect; and not only myself have never perceived fuch a flavour as the Doctor complains of, but this is the only complaint of the kind that I have hitherto heard of; though many perfons of the moft delicate tafte, and particularly many ladies, have used the water impregnated in my method for months together. Few perfons have had to do with bladders, and fixed air confined in bladders, more than myfelf; and yet I have never feen any reason to suspect this great folvent power of fixed air with respect to

them;

them; efpecially fo as to be apparent in the fpace of a few minutes.

But fuppofing the fixed air to be capable of diffolving the whole bladder, and to carry it along with itself into the impregnated water, no physician, or philofopher, will pretend to fay that it could have any more tendency to give it an urinous flavour, than if it had been any other membrane of the animal body.

Indeed, as the Doctor himself does not pretend to say that this ftrange urinous flavour was the effect of all the impregnations of water made in my method, but only in some of them (though it was generally fo, in those particular trials) it is evident, from his tacit confeffion, that it must have been an accidental thing, and could not have come from the bladder, which I fuppofe he made ufe of in all trials. For he has not done me the juftice to acknowledge that, in my pamphlet, among the various methods of effecting the impregnation of water, I have described one in which no bladder is made ufe of. When the Doctor fhall once more produce this urinous flavour (and as a new and curious experiment, it is certainly worthy of his farther investigation) taking care that no careless fervant fhall have mixed any urine in

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the

the water that he calls for, I fhall give this new objection to my process a farther examination. At prefent I am inclined to confider this as an experiment of the fervant, rather than of the Doctor himself.

Several perfons have thought that fixed air difcharged from impure chalk gives the water that is impregnated with it a disagreeable flavour, but this I have never obferved myself, and any other calcareous matter may be used in my method, as well as in that of Dr. Nooth, who recommends chalk, as the beft upon the whole.

I fhall conclude thefe animadverfions with doing what Dr. Nooth ought to have done before me, viz. fairly ftating the advantages and difadvantages of our two methods. His method requires lefs fkill in the operator, and a lefs conftant attention. It is alfo more elegant and cleanly, I mean with respect to the operator; for this does not at all affect the im

pregnated water. On these accounts I generally recommend and make use of his method myself, efpecially as the glaffes are made with improvements by Mr. Parker. But if Dr. Nooth be candid, he must acknowledge that my method requires much less time, and is much lefs expenfive, and therefore must be more pro

per

per when a great quantity of impregnated water is wanted; and especially when there is but little room to make it in.

My method indeed requires a constant attendance, but I queftion whether, upon the whole, more than is neceffary to be given to Dr. Nooth's method at intervals, if the water be at all agitated; confidering that mine does not require one-tenth part of the time. And though my method requires fome littleskill and address, it is not so much, but that many perfons, altogether unufed to experie ments, have, to my knowledge, fucceeded in it very well, and have made the impregnated water in a conftant way for their family ufe, and without any affiftance befides what they got from the printed directions. My apparatus cofts little or nothing, because no veffels are made for the purpose; and both the chalk and the acids are made to go as far as poffible, by means of the convenient agitation of the veffel in which they are contained. Whereas Dr. Nooth's method requires a peculiar and expensive apparatus, and more waste is unavoidable in the use of it. However, for the reafons abovementioned, I have never recommended my own method for the use of a family fince I have been acquainted with his.