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THE POPULAR SCIENCE MONTHLY. 



hot water, or by scraping. Such filters, 

 singly or in numbers, are placed in the bot- 

 tom of a cistern, the central pipes of efflux 

 being all connected together, and with one 

 outlet. Where a large filtering capacity is 

 required, a different principle is adopted, 

 viz., a series of carbon-plates. In this case 

 the water, in its passage from the inlet to 

 the outlet, is caused to pass through a num- 

 ber of frames, variously constructed, accord- 

 ing to circumstances. Thus there may be, 

 firstly, a frame, covered with fine wire 

 gauze ; then separate frames, paneled with 

 carbon-plates, with or without the interven- 

 tion of a bed of pure loose animal charcoal, 

 filling up the spaces between them; and 

 there may be also a double frame, containing 

 a sheet of felt compressed between two per- 

 forated plates, made respectively of sheet- 

 copper and zinc, which would exert a certain 

 electrical action, and aid in the chemical ac- 

 tion of precipitating impurities. The sys- 

 tem may be used for filtering the water- 

 supply of a town. 



Apart from this hygienic use, these car- 

 bon-blocks may be employed for many in- 

 dustrial purposes. Experiments have shown 

 them to be efficacious in removing delete- 

 rious gases, and other soluble substances 

 held in solution in fluids. They are applied 

 as filters for wines, oils, and syrups ; and, 

 above all, they merit attention as an adjunct 

 to the feed- water apparatus of steam-boilers, 

 inasmuch as efficient filtration affords the 

 best, cheapest, and surest method for pre- 

 venting incrustation in boilers. 



Cremation. — An eccentric will, wherein 

 the testator requested that his body might 

 be consumed in a gas-retort, and thus made 

 to contribute to the enlightenment instead 

 of the poisoning of the world, has survived 

 the long-forgotten subject of cremation. 

 "Without doubt, Mr. Trelawney's hideously- 

 graphic description of the burning of the 

 body of Shelley has greatly contributed to 

 prejudice the public mind against the clean- 

 est and best method of getting rid of the 

 " mortal coil." But the ceremony at Spez- 

 zia was conducted in the most bungling 

 fashion, and a want of scientific appliances 

 contributed to the incompleteness, and, 

 therefore, to the horror of a simple opera- 

 tion. A retort gets rid of the entire diffi- 



culty, and, both from a utilitarian, a scien- 

 tific, a sanitary, and a poetic point of view, 

 the mausoleum, decked with cinerary urns, 

 possesses immense advantages over the 

 damp and unwholesome graveyard, exhaling 

 pestiferous odors, to which modern nations, 

 for some inscrutable reason, are preposter- 

 ously wedded. — Iron 



Death of Dr. Forbes Winslow. — Dr. 



Winslow was born in London in 1810. He 

 began his medical studies in New York ; 

 took the degree of M. D. at King's College, 

 Aberdeen, and became a member of the 

 Royal College of Surgeons, London, in 1835. 

 His first published works appeared in 1831, 

 since which time he has made numerous 

 important contributions to the literature of 

 medicine, chiefly in the department of ner- 

 vous and mental diseases. His most valu- 

 able work in this line, " The Obscure Dis- 

 eases of the Brain, and Disorders of the 

 Mind," was published in 1860, and has since 

 passed through several editions. He died 

 in London, on March 4, 1874. 



The Economy of Beer. — Prof. Max von 

 Pettenkofer, the eminent Munich chemist, 

 states that, to make a quart of good beer, 

 there is required, at least, a pint of good 

 barley, besides hops, etc. The product con- 

 tains not a single trace of albumen, and 

 only a very small percentage of alimentary 

 principles : in short, it is only a condiment, 

 not a food-stuff properly so called. The 

 question now arises, Would it not be better 

 to send this barley to the mill, and make of 

 it a bread-stuff, instead of brewing from it 

 a costly beverage, which contributes little 

 or nothing to the system ? Or, better still, 

 Would it not be advisable to grow, in place 

 of barley and hops, wheat and rye, either of 

 which would give better bread than barley ? 



Prof. Pettenkofer holds that the need 

 of mere condiments is no less imperative 

 than the need of food-stuffs, properly so 

 called. " Butter and cheese," says he, " are 

 neither as good nor as complete food- 

 stuffs as milk, and yet butter and cheese 

 are made, and will continue to be made, 

 even though it were possible to transport 

 milk in good condition to considerable dis- 

 tances." The same is to be said of barley 

 and beer. Prof. Pettenkofer observes that 



