360 Chemical Examination of the Bath Waters, 



From the experiments which I have made, and which I have varied in every way I could 

 devife, as will hereafter appear, it feems that the celebrated philofopher Mayow made his ex- 

 periments on the waters after they had been fufFered to' cool. He fays, " Quod ad vittiolum, 

 denique fpeftat, balneum vulgo diftum balneum crucis, item akcrum praefervidum nominatum, 

 vitriolum plane nullum continere videntur ; etenim fi gallae contufae aquis thermarum diflarum 

 infufse fuerint ; aquse iftse colorem purpureum aut nigrum nequaquam habituras funt ; quod 

 tamen omnino contingeret, fi thermae iftas vitriolo imbutae eflent. Quod ad balneum regis, 

 (fie di(Slum) iftoc vitrioli tantillo imprxgnari videtur; quippe fi gallae contufae, ejus aquae 

 injiciantur, eadem colore atro-purpureo leviter tingetur." I have found upon repeated trials, 

 that the King's-bath water will affume a purple tinge on the addition of tindlure of galls, 

 when warm, and even when it has been recently cooled, but not the leaft colour after it has 

 remained cold for any length of time. It appears from the experiments which 1 have made, 

 that a fmall portion of iron is diflblved by the carbonic acid, and that this acid by evaporating 

 leaves the iron unfufceptible of any change of colour by the addition of galls. Mayow's ob- 

 fervations on this circumftance confirms my opinion, and are perfectly confiftent with the 

 fadts I have obferved. He fays, " Annotandum efl: autem, quod minera quasdam indolis me- 

 tallicae una cum Thermarum praedidtarum Scaturiginibus e Terra prorumpat ; quae facile 

 in vitriolum convert! poteft : etenim fi fabulo (quod una cum aquis Thermarum e Terra 

 erumpens, in fundo balneorum reperitur) liquor quivis acidus fuperfundatur, idem non fine 

 efFervefcentia fatis infigni a menftruo acido corrofum, ex parte aliqua in vitriolum conver- 

 tetur ; baud fecus ac limaturae ferri a liquore acido corrofae, contingit : quippe fi fabulum 

 iftoc balneorum liquore acido impregnatum, infufioni gallarum injiciatur, liquor mox co- 

 lorem atro-purpureum acquiret : cum tamen, fi infufio Gallarum fabulo ifti recens a balneis 

 exempto, non vero a liquore acido jam corrofo, afFundatur, ea nequaquam colorem purpu- 

 reum obtinebit, indicio utique manifefto, fabulum balneorum metallicum, non nifi a men- 

 ftruo acido corrofum, indolem vitriolicam induere. 



Advertendum eft autem, quod fabulum iftud thermarum aliquandiu fervatum, aerique 

 expofitum fponte fua in vitriolum commigrabit : quippe fi iftius modi fabulum gallarum in- 

 fufioni injiciatur, aqua mox colorem atro-purpureum habitura eft. Quinimo fi idem lin- 

 gua imponatur, fapor vitriolicus fatis manifefte fe prodet. 



Nimirum fpiritus nitro-aereus cum minera metailica, five marchafita falino-fulphurea 

 (e quali vitriolum confici folet), fabulo didto admifta tradlu temporls congreditur, et efFer- 

 vefcit; eamque tandem modo alibi oftenfo, in vitriolum convertit." 



Here we cannot help admiring the extent of Mayow's mind, who, without the aid of mo- 

 dern fcience, could fo accurately defcribe the caufes which produce the vitriol he fpeaks of. 

 Allowing his fpiritus nitro-aereus to be oxygen, his theory it perfectly confiftant with, all 

 the modern difcoveries ; the iron, by acquiring the fpiritus nitro-aereus, or oxygen, becomes 

 ochre or ruft, and is then foluble in acids ; or if it (as he obferves) be united with fulphur, 

 the fulphur acquires his fpirititus nitro-aereus, is converted into vitriolic acid, which com- 

 bining with the iron, forms vitriol of iron, and is then affected by an infufion of galls. 



That 



