M U R

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gaffes have any action on muriatic acid, withammoniacal gas however it combines inftan-taneoufly, the two airs if rightly proportionedto each other entirely difappearing and folidmuriat of ammonia being the refult.

Although muriatic acid when in the ftate ofgas is the pureft form in which it is known, yetthe inconvenience of keeping and applying anyfubltance in this ftate being very great, it isalways ufed except on particular occafions in aliquid form. Liquid muriatic acid, or fpirit offait, is prepared in the following manner. Acapacious tubulated retort is filled about one-third of its capacity with decrepitated commonfait (muriat of fodaj, and the juncture of theretort with the receiver is carefully clofed withfat lute : to the receiver is adapted a Woulfe’sapparatus, the bottles of which are placed in aframe or fmall ciftern for the fake of keepingthem cool by means of ice and water. TheWouife bottles themfelves are more than halffilled with diftilled water, and then concentratedfulphuric acid, in the proportion of about 6ounces for every pound avoirdupois, is pouredupon the lalt through the tubulure of the retort,which is immediately after clofed with its glafsftopper. As foon as the acid and fait come intocontact, the retort and receiver are filled withwhite vapour, and the difengagement of muri-atic acid goes on for fome time without theapplication of heat: when the current of gasthrough the Wouife bottles begins to fiacken, apot of lighted charcoal ihould be placed underthe retort, gradually increafing the fire till at avery low red heat no more gas is difengaged.What remains in the retort is now dry fulphatof foda, and the water in the Wouife, bottleswill be found to be more or lefs impregnatedwith muriatic acid according to the quantity offait originally made ufe of. The method pur-fued in the manufacturing laboratories in Eng-land is in general the fame as that mentionedabove, but with a greater fimplicity of appara-tus, and the veflel that performs the part of theretort is either of earthenware or of iron ; thislaft however is extremely improper, as a portionof iron always rifes with the acid and thuscommunicates to it that yellow ftraw colourwhich diftinguilhes common muriatic acid. InGermany , where fulphuric acid is dearer thanit is in this country, the mode of manufacturingthis acid is to mingle accurately one part ofcommon fait with four of dried clay, and tofubjeft the mafs to ftrong ignition in iron orearthen veffels ; at a high temperature the alka-b Gren. Syli, Hand, der Chitu. i. p. 447. c Prieliley.

line bafe of the fait combines with the earth,and the gaffeous acid as it pafl'es over is receivedinto water where it is condenfed in the ufualway, b

If a portion of water be confined in a jar overmercury, and muriatic acid gas be let up intoit, a quantity of gas equal in weight to thewater will be abforbed, while its bulk will beincreafed, according to Dr. Prieftley, from 1 to1.5, and according to Ivirwan from 1. to 1.33 :hence the fpecific gravity of this liquid acid,according to the former, is = 1.33, and accord-ing to the latter = 1.5 : but the fpecific gravityof the ftrongeft muriatic acid that can he madeand kept in the common method does not ex-ceed at 6o° Fahr. 1.196. Pure liquid muriaticacid is as colourlefs as water; when expofed tothe air it emits a white vapour; it affecSts thefmell and tafte in the fame manner as the mu-riatic gas does : it combines with the alkaliesand earths, forming neutral falts. Its afitionupon iron and zinc is very rapid and accom-panied by a copious difengagement of hydrogengas; at a boiling temperature and in open vef-fels it oxydates and difiolves copper, tin, bif-muth, lead, cobalt, manganefe, antimony, andarfenic ; filver is alfo a fie fled by it though veryflightly; it feems to have no action whateveron gold, platina, mercury, tungften, molybdena,tellurium and titanium. It diffolves all themetallic oxyds and is an acid of remarkableactivity. When heated for fome time in clofedglafs tubes it corrodes them very fenfibly, takingup the oxyd of lead from the white glafs andthe alkali from green glafs. c

Muriatic acid is capable of decompofing inpart the ftrongeft nitric acid, being itfelf at thefame time converted into the oxygenated mu-riatic acid, as may be feen more at length inthe article Nitro-muriatic Acid. For thefame reafon alfo the alkaline nitrats are decom-pofable by muriatic acid, as has been ably ftiownby Cornette. d

Various attempts have been made to decom-pofe the muriatic acid, and becaufe in molt ofthe experiments a quantity of hydrogen madeits appearance, this fubftance was fuppofed bymany to be the aciclifiable bafe of the acid. Frommore recent and accurate examinations howeverit appears highly probable that the hydrogen inall thefe cafes arifes not from the decompofitionof the acid but of tjie water, which it alwayscontains in a greater or lefs proportion. Thernoft fatisfaftory experiments relative to thefuppofed decompofition of muriatic acid arc

i Mem, de l’Acad. des Sciences for 1778, pp. 44 — J 33 -•p 2