PETROLEUM.

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skin diseases, as ringworm. The quantity of creasote in it may beincreased or diminished according to circumstances. When used byway of friction, eight or ten drops of creasote to the above quantity oflard may be sufficient.

Lotions, gargles, or injections of creasote, are prepared by dissolvingfrom two to six drops (according to the circumstances of each case) in anounce of water. A solution of this kind is sometimes mixed withpoultices.

The inhalation of creasote vapour may be effected by diffusing a fewdrops of creasote through water or a mucilaginous liquid, and breathingthrough this, by means of the ordinary inhaling bottle (see p. 51).

Antidotes. —In a case of poisoning by creasote, the depression of thevital powers is to be counteracted by ammonia and other stimulants.Mr. Cormack suggests the use of chlorine, but the value of this agenthas not been determined by actual experiment. Oleaginous and mucila-ginous drinks are recommended by Comeliani, for the purpose of pre-venting the local action of creasote on the mucous lining of the stomachand intestines. Vinegar does not diminish, but, according to Comeliani,increases its activity. Mr. Cormack says albumen augments its poison-ous operation. Bleeding is suggested by this writer, in order torelieve the distension of the heart, and thereby to excite the contrac-tions of this viscus. Artificial respiration should on no account beomitted. Any intlammatory symptoms which may subsequently appearare of course to be treated by the usual antiphlogistic measures.

Petroleum. — Petro'leum.

History. —Herodotus ( Melpomene , cxcv.) mentions the petroleumsprings of Zacynthus (now called Zante ) more than 400 years beforeChrist. The substance known to mineralogists as petroleum is the blacknaphtha (piXav) of Dioscorides (lib. i.), the bitumen liquidum of Pliny (lib. xxxv.)

Natural History . —There are two varieties of liquid bitumen ormineral oil: one is transparent and nearly colourless, or only slightlyyellow, and when burnt leaves no residuum; the other is thick, of areddish brown colour or blackish, and leaves, after combustion, a blackcoal. The first is called naphtha (a Chaldacan word); the secondpetroleum (from petra, a rock ; and oleum , oil) or rock oil, because it isfrequently found exuding in the form of an oily liquid from rocks. Bothkinds are supposed to be produced by the decomposition of organic(vegetable) matter, for they are always found in Neptunian rocks, andthey appear sometimes to be one of the products of the decomposition ofcoal (Berzelius , Traite de Chim. t. 6 me .) From the investigation ofDrs. Christison and Gregory (Tr. Roy. Soc. Edinb. vol.xiii. p. 1), it appearsprobable that some varieties of petroleum, as that of Rangoon, are pro-ducts of destructive distillation, since they contain paraffine and eupion,substances obtained from organic bodies by heat.

Petroleum is found in this country at Onnskirk in Lancashire , atColebrook Dale in Derbyshire, and at St. Catherine’s Well near Edin-burgh. In France it is produced at the village of Gabian in Languedoc ,and hence it was termed Oleum Gabianum. It is also found in variousother parts of Europe, especially in Italy. In the United States of