370 Dr. Spurxheuii s demonslraliue Counts of Lcclures 



pound ; — and a chaldron of coals has produced to me thirty- 

 two pounds of essential oil ; this I could sell at sixteen guineas 

 a hundred weight. — With regard to the quantity of asphaltuni, 

 from one chaldron of coals I obtained from tw?uty-eight to 

 thirty-two pounds ; this I could sell at ISO*, th.e hundred weight. 

 — The quantity of ammoniacal liquor amounts to one hundred 

 and eighty pounds, that is, about eigliteen gallons ; and fourteen 

 hundred weight of ammoniacal liquor produced half a hundred 

 weight of carbonate of ammoniac, this sells at about sixteen 

 guineas the hundred weight ; and fourteen hundred weight of 

 ammoniacal liquor, if it be converted into muriate of ammoniac, 

 will produce a hundred weight of muriate of ammoniac, which 

 i.s worth fourteen guineas. 



" Question. — What do you reckon the price of a hundred 

 weight of coals ? 



" Ansuer. — I reckon a chaldron of coals at retail price (ios. ; 

 and I take a chaldron of coals to be about twenty-eight himdred 

 weight. 



" Queslion. — Descri!)e how pitch and asphaltum are pro- 

 duced ? 



" Answer. — The oil spoken of before is obtained by sub- 

 mitting the tar to a sini])le distillation ; by contliming the same 

 process, an additional quantity of essential oil of an inferior 

 quality is produced, whilst the consistence of the tar becomes 

 diminished, and then approaches to a state of pitch. By a 

 further application of heat, and consequent subtraction of an 

 additional quantity of oil, the pilch becomes converted into an 

 asphaltum, which is to be purified in the usual manner." 



Anxious as we are to a\ oid the charge oi encouraging vision- 

 ary speculation, we cannot help anticipating the extensive in- 

 troduction of the gas lights into private houses as at no great 

 distance. Mr. Arkerman in tiie Strand b.as set the example ; 

 the whole of his house, from the kitchen to the drawing-room, 

 his extensive warehouses, shop, printing-office, and manufactory, 

 is now and has for some years been lighted solely with carbu- 

 retted hydrogen or coal gas. 



LIX. Dr. Sfi'rzhei.'sj's demoiuiralive Course of Lectures on 

 Drs. Gall and Si'i/rzhiiIm's T hysiognomonicaL System. 



[('oiuimjed from jiajjcSia.] 



Lecture A*. X HKJjrain is an aggregation of organs ; from birth 

 to the period of declenaiou in age, its figure may be ascertained, 



* Delivered Friday, Of touer 28. 



