34 PLYMOUTH INSTITUTION. 



comparatively small quantity of fuel is due, therefore, to the presence 

 of water : oxygen constitutes only one fifth of the air admitted to a 

 furnace, the remaining four fifths taking no part in the ignition of 

 the fuel. In the process here described, oxygen, instead of being 

 admitted in any great quantity from without, is generated within the 

 furnace ; and instead of its being accompanied by azote, which re- 

 tards combustion and extinguishes flame, it is accompanied by 

 hydrogen, one of the most inflammable of the gases. There is per- 

 haps no purpose for which heat is required in an enclosed furnace 

 to which the process is not applicable. Steam engines, whether 

 stationary or locomotive, breweries, distilleries, glass-houses, the 

 cabouse of the merchant ship, and the galley of the man of war are 

 favourable situations for its employment. 



DECEMBER 5Tii. Mr. P. SWAIN, On Insanity. 



In the introduction the lecturer pointed out the antiquity of in- 

 sanity, proving that it was coeval with the human passions. He 

 spoke of allusion being made to it in the book of Job, which is the 

 most ancient record we possess, and adverted to several examples of 

 insanity recorded in fabulous tradition. 



He next proceeded to recount the opinions entertained of old, 

 relative to the nature of insanity, which, he endeavoured to show, 

 were regulated by the notions held by the ancients respecting the 

 nature of the mind. He made mention of some of the methods of 

 treatment used by the priesthood, upon whom the care of the insane 

 chiefly devolved. 



Idiotcy was next described, which the lecturer believes to consist 

 in a deficiency of the mind, dependent on defect of the brain ; and 

 he exemplified this part of his subject by a description of the 

 Cretins, a race of idiots in the Valais of Switzerland. He stated that, 

 notwithstanding their mental and corporeal deficiencies, they are 

 the objects of the kindest solicitude, being regarded by the Swiss 

 peasantry with religious veneration ; and remarked the extraordinary 

 difference in the effects of superstition on a community. In Swit- 

 zerland the idiot is cherished and revered ; in some countries the 

 imbecile or deformed offspring is consigned to starvation by its 

 flinty parent, or sacrificed on the altar as the peculiar property of 

 some loathsome demon. 



The lecturer then proceeded to define insanity, and to divide it 

 into mania, melancholia, and hypochondriasis. 



In speaking of the extraordinary fancies by which the hypochon- 

 driac is sometimes beset, he related a curious anecdote of the late 



