Bath Waten. — Talhw Lamp, 363 



going experiment, I added to the clear fluid which came through the filtre a folution of 

 pure ammonia, which caufed a precipitation. Now from Profeffor Bergmann's table, and 

 from direft experiments before related, I learn that pure ammonia has for the fulphuric and 

 marine acids a lefs attraftion than magnefia ; but pure ammonia, as before mentioned, has a 

 greater attraction for thofe acids than clay ; confequently it is evident that this precipitation 

 is clay. There appeared this feparation in the three waters of the baths, but there is a great 

 difFerence in the quantity of precipitate. The Hot-bath waters contain more than the King's- 

 bath, and the King's-bath more than the Crofs-bath waters. 



When the waters of the feveral baths are warm, and fre(b from the fpring*, there is an 

 evident difcolouration on the addition of infufioa of galls^ plainly indicating the prefence of" 

 iron. 



Two ounces of the waters frefh from the bath were mixed with a folution of fugar of- 

 lead; each produced a conGderable milkinefs, and the colour remained perfedlly white. On 

 the addition to each of a quarter of a grain of fulphuret of potafli, an evident difcolouration^ 

 took place, indicating the prefence of fulphur. From this, as from many other experiments, 

 J am convinced that there is no fulphurated hydrogenous gas produced by the Bath 

 waters. ' 



When filver-leaf was placed in a veflel containing thefe waters frefli from the pumps, it re- 

 mained of the fame brightnefs and white colour, but on the addition of fulphuret of-potafh it- 

 sJTumed an almoit black colour. 



iXo he continued.) 



X. 



Gonjlrudiitit'ofa Lamp for Burning Talhw. By Mr. WilxTAM ClosE. 



To Mr. NxcHOLsoN. 



HE conftruiSion of a lamp for burning tallow fome time ago engaged my attention, 

 and my endeavours were attended with fome degree of fuccefs. As the contrivance is very 

 fimple, and likely to favc confiderabk expenee in the article of illumination, I have fent you 

 a defcription of it, which I hope may not be unacceptable to fome of your readers. 



It was the perufal of the obfervations formerly made by yourfelf upon the fame fubj$£i-*' 

 that firft induced me to make the attempt. 



I am, fir, your humble fervant, 

 Dabith Sep. ■^Oyij<j(j, WiifcUM CtosJE. 



* FhiJofophical Journal, L 67. 



