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THE POPULAR SCIENCE MONTHLY. 



clock-work arrangement. In order to do 

 this, he contrived a tortoise-shaped diving- 

 boat of iron plate, which contained air 

 enough to supply a man for half an hour. 

 This boat was propelled by a sort of screw, 

 and guided by means of a compass made 

 visible by phosphorus. The torpedo was 

 carried outside of the boat, but could be 

 detached by the concealed operator with- 

 in. It was connected by a line to a 

 screw, which was to be driven into the bot- 

 tom of the hostile ship. As soon as this 

 was effected, the torpedo was to be cast 

 off, when it floated against the vessel's side. 

 The action of casting-off set the clock-work 

 going and then the operator had time to 

 retire to a safe distance before the catas- 

 trophe. This torpedo and submarine boat 

 were actually tested against an English sixty- 

 four-gun brig early in the War of Indepen- 

 dence, but the attempt to blow up the ves- 

 sel was unsuccessful. No further effort ap- 

 pears to have been made to turn this inven- 

 tion to account. Nevertheless, to Bushnell 

 the honor belongs of having been the first 

 to destroy a vessel by a torpedo. In an 

 attack on the Cerberus frigate with a towed 

 torpedo, he blew up a schooner astern of 

 the frigate, and killed three or four men on 

 board. This schooner was the first vessel 

 ever so destroyed. 



Human Stature Treating of " Human 

 Stature," a writer in the Revue & Anthropo- 

 logic gives 1.585 metre (about 5.199 feet) 

 as the lowest mean stature of males among 

 the Esquimaux, while in some tribes of the 

 same race the mean reaches the compara- 

 tively high figure of 1.708 metre (about 

 5.60225 feet). This flatly contradicts the 

 belief that cold climates produce only men 

 of low stature. Among the Lapps the 

 mean stature of men is 1.535 metre, and of 

 women 1.421 metre. The Fuegians, so far 

 from being diminutive, are above the aver- 

 age stature of the human race. The Bush- 

 men rank among the most diminutive, the 

 average stature of both sexes being under 

 1.400 metre. The Akkas attain precisely 

 the same average. The mean stature of six 

 Obongo women, measured by Du Chaillu, 

 was 1.428 metre. Neither the Negritos nor 

 the Andaman-Islanders can compare for lit- 

 tleness with the Bushmen of South Africa. 



On the other hand, according to this author, 

 the highest stature is attained by the Nor- 

 wegians, in Europe, the Kaffirs in South Af- 

 rica, some Indian tribes in North America, 

 the Polynesians, and the Patagonians. The 

 mean stature of the last-named people, ac- 

 cording to the statements of the most trust- 

 worthy observers, is 1.781 metre (5.84169 

 feet) ; the mean of natives of the different 

 Polynesian archipelagoes is 1.762 metre 

 (5.77937 feet). The mean stature of the 

 human race is about 1.600 metre (five feet 

 three inches). 



Artificial Ice. We select from a report 

 in the Lancet, on " Ice-making Machines," a 

 description of a machine designed to pro- 

 duce ice on the large scale. A cistern, 

 somewhat like a tubular boiler, contains 

 some ether, which is the refrigerating agent. 

 The vapor escaping from the ether is 

 pumped, by a double-action air-pump, into 

 a condenser surrounded by cold water; 

 thence the ether, now once more liquid, 

 flows back to the cistern. The evaporation 

 of the ether causes the cistern to become 

 intensely cold, and this cold is rapidly com- 

 municated to a strong solution of common 

 salt, in which the cistern is immersed. The 

 very cold brine so obtained is caused to 

 circulate through flat, hollow, and vertical 

 partitions of tinned copper, in a tank filled 

 with pure water. Ice quickly forms in 

 smooth slabs on the partitions, and is from 

 time to time removed as the slabs acquire 

 the requisite thickness. The ice so ob- 

 tained is, of course, exceedingly pure, and 

 is said to waste less and cost less than 

 natural ice. In this machine the ether is 

 condensed again and again with scarcely any 

 loss, and the only expenses after the origi- 

 nal outlay are, therefore, for rent, fuel, and 

 labor. 



Mineral Caoutchouc. In presenting to 

 the Academy of Natural Sciences of Philadel- 

 phia specimens of mineral caoutchouc from 

 South Australia, Mr. Galloway C. Morris 

 stated that the substance is found during 

 the dry season in a limited area of country 

 of a swampy nature in the Coorong district. 

 It occurs in sheets from the thickness of 

 writing-paper to about five-eighths of an 

 inch. It is made into illuminating oil. Of 



