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THE POPULAR SCIENCE MONTHLY 



applications. Borax and boric acid, which 

 are included in the four receipts here given, 

 are very fusible, and are not changed by 

 heat, but only by an excess of moisture 

 in the air, and well fulfill the first condition. 

 Hydrochlorate, carbonate, and sulphate of 

 ammonia readily give off incombustible 

 gases, which have also the positive quality 

 of extinguishing combustion, and thus ad- 

 mirably fulfill the other condition. Hence 

 the compositions recommended possess all 

 the desired qualities. They have also re- 

 sponded satisfactorily to varied tests of ex- 

 periment. 



A New African Region. The Rev. 

 David Asante, a native missionary of the 

 Basle Gold Coast mission, Africa, recently 

 visited during a journey of exploration the 

 hill-country of Booso, where he says the 

 temperature is cool, rains are frequent, and 

 rivulets numerous. The country is thinly 

 peopled by a population subject to goitre 

 and extremely dirty, whose children and 

 bachelors wear no clothing. Wives, being 

 harder to get by the process of wooing 

 and winning their consent than in most 

 African countries are treated well. The 

 fetich-worship is less subtile than on the 

 coast, but the poison-ordeal is frequently 

 resorted to, and accounts for the small 

 population. Wben a person dies, a whole 

 village sometimes submits to take an in- 

 fusion of a poisonous bark. Quarrels are 

 settled by resorting to the same dangerous 

 arbiter, thefts are discovered by it, babies 

 who cry much are made to swallow the in- 

 fusion to prevent their growing up wicked, 

 and parents who lose several children in 

 succession take it in order that the cause 

 of their affliction may be discovered. 



Petrolenm Prodnets as Fnel. The resi- 

 dues of the distillation of petroleum have 

 been employed in the Caucasus for several 

 years as a combustible, and have appreciated 

 from having no value in 1874 till they com- 

 mand a price six times higher than crude 

 naphtha, which is now employed as a cheap- 

 er fuel. Naphtha has been considered dan- 

 gerous on account of its explosive qualities, 

 but it has been found that they disappear 

 when the liquid ha* been exposed to the 

 air for a few days till it has lost its volatile 



constituents, which compose about fifteen 

 per cent of its substance. Crude naphtha, 

 right from the springs, is burned in the lo- 

 comotive-furnaces of the Balachanskoi rail- 

 road, and there are no accidents. Naph- 

 tha is the fuel that develops the greatest 

 quantity of heat, and it also possesses the 

 great advantage of not containing sulphur 

 or other injurious substances. Ninety per 

 cent of the theoretic calorific power can be 

 realized from it, while not more than sixty 

 per cent can be got from solid combustibles. 

 In 1859, doubts were expressed in Russia 

 as to whether petroleum could be used as a 

 combustible ; now it is employed exclusively 

 on all the ships in the Caspian Sea, and only 

 half as much of it is required as used to be 

 consumed of coal. The maximum force to 

 be obtained from petroleum is equivalent 

 to two and a half times what coal will fur- 

 nish ; and experiments on the railroad from 

 Baku to Balachan show that a given weight 

 of naphtha will take the place of eight and 

 a half times the weight of wood, although 

 the theoretically calculated difference in 

 calorific power is only as three to one. 

 Petroleum is very conveniently introduced 

 into the furnaces of locomotives with the 

 injectors that are used; the combustion is 

 very easily regulated, and the furnaces last 

 well in the absence of sulphur, while no 

 smoke, sparks, or ashes, are emitted. 



Make Room for City Children. Dr. James 

 B. Russell, health-officer of Glasgow, while 

 he admits that the moral delinquencies of 

 parents, and particularly drunkenness, are 

 important factors to the death-rate of chil- 

 dren in cities, insists that too much influ- 

 ence should not be attributed to them. The 

 child of sober, industrious parents, in a city 

 of good sanitary conditions, still lacks room 

 for his complete well-being. The element 

 of space comprehends all the physical condi- 

 tions of health so completely that the name 

 density is recognized by vital statisticians a9 

 the best standard of comparative measure- 

 ment. Then, as the child grows up, comes 

 the natural desire for play and exercise, 

 which is essential for health and growth. 

 Pent up as city children are, their play be- 

 comes in great part mischief. The prevail- 

 ing characteristics of children's play corre- 

 spond with the manners, habits, and occu- 



