BAT 



BAT 



■ace, or elfe to heat them afrcfh, and tlirow them into hot 

 water: which is afterwards to be ufed, cither in the way of 

 bath or fomentation occafionally. There arc other artifi- 

 cial baths, prepared of alum and quicklime by boiling them 

 tog-tther in iine rain-water. Such baths are highly fervice- 

 able in paralytic diforders and weaknefs of the limbs. 



T\\e pcpptr bath, or pfjfer •wajfer on the Alps, is one of 

 the moll celebrated in Europe, and has been the fubjedl of 

 particular treatiL-s, befides what has been faid of it occafi- 

 onally by Scheuchzer and others. It was firft difcovercd in 

 the year 1 240, and is of the periodical kind. The water 

 bi-eaks forth in a dreadful place, fcarce accefiible to the fun- 

 beams, or indeed to men, unlefs of the greatell boldnefs, 

 and fuch as are not in the lead fubjeft to dizzincfs. Thefe 

 baths have this fingularity above all others, tiiat they com- 

 monly break forth in May, and that with a fort of impetuo- 

 fity, bringing with them beech leaves, crabs, or other wood- 

 fruit ; and that their courfe defills in September or Octo- 

 ber. 



Scheuchzer profcHes himfelf of opinion, that thefe wa- 

 ters are not impregnated with any minerals ; or, if they do 

 contain any, that tiieir virtues in curing diftempers and pre- 

 ferving health, do not proceed from them. They are ex- 

 ceedingly clear, dcllitute of colour, tafte, or fmell. Phil. 

 Tranf. N^ 316. p. 151. 



Bath, Balneum, in Chem'ijlry. In many chemical pro- 

 cedes it is of the utmoft importance both for the fecurity of 

 the vcffels, and the fucccfs of the operation, that the appli- 

 cation of the neceffary heat (hould be gradual and regulated. 

 This is particularly the cafe in moil dillillations, and in di- 

 geftions at a moderate temperature, and wherever glafs vef- 

 fels are employed. Hence the contrivance of baths or in- 

 termedes between the burning fuel and the vcfltl containing 

 the fubjett of the procefs, in which the veffels are im- 

 merfed, and whereby they receive the heat in a regular gra- 

 dual manner. As fluids heat with more uniformity than 

 folids, tliey are preferable where only a heat a little infe- 

 rior to the boiling point of the fluid is required ; and they 

 poffefs this important advantage,, that the heat is fo kept 

 down by evaporation, that it can never rife beyond the 

 known and given point of boiling. But where as much 

 even as a low red heat is required, no fluid can be employed 

 with any convenience, and recourfe mull be had to fome in- 

 combuftible folid reduced to powder. A great variety of 

 baths were invented by the elder chemifts, efpecially thofe 

 who were engaged in alchemical purfuits, which were fup- 

 pofed to require long digeftions in a very accurately regu- 

 lated heat ; but mod of thefe are now laid afidc, and only 

 the following kinds of baths are retained. 



The Water Bath, Balneum Aqutc, is of great ufe in the di- 

 ftillation of effential oils, of the aromatic part of vegetables, 

 of the finer kinds of ardent fpirits, in evaporating into dry- 

 nefs the folutions of vegetables employed in medicine whofe 

 virtue would be loft by any excels of heat, and in many 

 other proceffes. The apparatus for this bath forms part of 

 the improved Alfmbic (which fee, in P/atelll. ^g-i^- 

 A. of Chemi/hy) ; but any veflel full of water, capable 

 of being heated to boiling, and of containing a retort or 

 other veflVl, may be ufed as a water bath. As the utmoft 

 heat which any fubftance immerfed in a boihng liquid can 

 acquire thereby, falls (hort by a few degrees of the tempe- 

 rature of the liquid itfelf, the heat of a water bath cannot 

 amount to 212°. This is confiderably increafed, however, 

 by ufing a llrong folntion of fea-falt, or any other fait, 

 inftead of water ; as the boiling point of faturatcd brine 

 is much higher than that of mere water. This forms the 

 ancient Balneum Blarie, Bath of Mary {the I'ir^'m, as fome 



have interpreted the term) ; but others with more plaufibiKty 

 write Balneum Maris, fea- 'water, or brine-bath. 



Mercury, the fufible alloy of bifmuth tin and lead, tin 

 alone, and other metals, have been propofcd for the purpofc 

 of baths, and nor/ and then ufed, when a higher heat tlian 

 the falt-water bath was required ; but the metals are cum- 

 berfome by their weight, expenfivc, mercurj' dangerous to 

 the byc-llander from its evaporation, and they all have the 

 inconvenience of requiring more prefiure to be ufed than 

 the mere weight of the fubftance which they are to heat, to 

 enable it to be immerfed in the melted metal. 



Balneum Siccum. This whimfical term has been applied to 

 the vapour bath, in which the vefTel to be heated is tnclofed 

 in a kind of cafe filled only with the fteam of boiling water. 

 It is almoft if not quite o\it of ufe for chemical purpofes, 

 but it forms a valuable implement for the kitchen. 



Balneum Arenx, Sand-bath, of all kinds of chemical baths 

 that which is ufed the moll extenfively. In experimental fur- 

 naces, or fmaller chemical operations, the veftcl to contain 

 the fand is of cafl: iron, very much in the form of an in- 

 verted round hat, of which the hollow part is fupported by 

 the projedling rim upon the fides of the furnace, and hangs 

 down over the burning fuel, the flame of which plays round 

 it and gradually heats the fand which it contains, together 

 with ever}- veifel buried therein. The fand fliould be of 

 middling finenefs, the finell as well as the very coarfeft 

 being feparated by fifting ; for by this means the heat is 

 more gradually dittributcd. Thofe diftillations, which at 

 any part of the procefs require as much as a low red heat, 

 are ufually performed in fand baths, even in manufafturea 

 in the great way, as of aqua fortis. Sand, when thorough- 

 ly heated, continues hot for a very confiderable length of 

 time. 



Bath is alfo ufed in another fenfe, to fignify the fufion of 

 metallic matters in certain operations : thus, in refining or 

 cupelling, the metals are faid to be in bath when they arc 

 melted. 



Baths, the name proper to fuch public or private edi- 

 fices as are ufed for bathing. 



The praftice of bathing is found among all the nations of 

 antiquity. The people of the Eaft were ever accuftorr.ed to 

 it, and have continued the habit to the prefent time ; their 

 methods being perfedly conformable to thofe of ths Greeks 

 and Romans. If we may credit Homer, Mofchus, and 

 Theocritus, the firil ages of Greece knew no other hatha 

 than the rivers ; and it was in them that the princefles Nau- 

 ficaa, Europe, and Helen bathed. Homer (fay the French 

 Encyclopedifts) indicates, that in his time private baths of 

 a regular form were in ufe. Telemachus and Pififtratus, 

 they obferve, were conduced to baths of uncommon neat- 

 nefs: the moft beautiful Haves in the palace bathed them, 

 perfumed them, and adorned them with the handfomeft 

 garments. But all this is an aflTumptien which the text of 

 their author by no means warrants. The paflage alluded 

 to is in the Odyfley, book xv. 1. 1 35. 



X£f;'i,'5a dVjuL^t^oXo; ^r^o;^^!* l-rr^-^iva^ ^i^d7x 

 Kcc'/.r, p^^vr'.iri, vrif ccfyx. f^iio Xs^hto; 



And the lines which follow plainly fliow, it was nothiflg 

 more than a common ablution previous to an entertainment. 

 The Ai,5»{ was a kind of vafe occafionally placed upon a. 

 tripod. 



The Romans, who for a long time bathed in the Tybcr, 

 borrowed the idea of artificial baths from the Greeks ; thei;; 

 various habits of Ufe and drefs rendered fuch accommoda- 

 tions neceflary ; and, to make (hort of our relation, all the 

 moll fplendid and fafcinating luxuries of the emperors were 

 5 H 2 multi- 



