POPULAR MISCELLANY. 



565 



light-hearted and impulsive, because he lives 

 in an easy country, with a soft climate and 

 rich soil. The Highlander is rugged and 

 stern, because his country, where " he has 

 to fight with the elements a never-ending 

 battle, wherein he is often the loser," is so. 

 The apportionment of lands into cultivated, 

 pasture, and feral lands, rests upon geological 

 causes, which determine that each tract shall 

 be used for the purposes by which the most 

 can be made out of it. The sites of towns and 

 villages may often be traced to a similar in- 

 fluence. Formerly they were built around 

 heights that could be fortified ; now they are 

 built where the geological features afford the 

 most scope for industrial and commercial 

 development ; and the latter towns are the 

 ones that are growing, and to which the 

 population is being transferred at the ex- 

 pense of the others. The style of archi- 

 tecture, which is largely determined by the 

 presence or absence of building-stone, and 

 the kind of the stone or clay, is obviously 

 related to geological features. Lastly, " the 

 history of the development of our system 

 of railways, our steam machinery, our man- 

 ufactures, is unintelligible except when 

 taken together with the opening up of our 

 resources in coal and iron," and these are 

 traceable wholly to geological features. 



A New Weighing of the Earth. Pro- 

 fessor von Jolly, of Munich, has recently 

 employed a new process for the determina- 

 tion of the mean density of the earth. He 

 placed a pair of scales in the top of a tower, 

 and attached to each plate of the instrument 

 a wire which reached, passing through a 

 zinc tube, to twenty-one metres below. To 

 the lower ends of the wires other scale 

 plates were suspended, which thus hung 

 within a little more than a metre of the 

 ground. Under one of the lower plates he 

 put a ball of lead, a metre in diameter. The 

 fact that a body at a certain elevation gains 

 in weight as it is brought nearer to the 

 ground was verified by weighing bodies first 

 in one of the upper balances and then in one 

 of the lower ones. Furthermore these bodies 

 varied in weight in the lower plates accord- 

 ing as the mass of lead remained under 

 them or was taken away. The differences in 

 these weights showed the degree of attrac- 

 tion exercised by the mass. The value 



thus obtained, compared with the attraction 

 exerted by the earth alone, furnished a means 

 of ascertaining, according to the laws of 

 gravitation, the ratio between the density of 

 the earth and that of lead, and, the latter 

 being known, of determining the mean den- 

 sity of the globe. M. von Jolly's experi- 

 ments give this density as 5 - 692, with a prob- 

 able error of 0*068, a figure that agrees 

 quite well with other determinations, par- 

 ticularly with Bailey's of 5 '6 7. 



Recent Applications of Science to Ma- 

 chinery. Sir Frederick Bramwell took as 

 the subject of his chairman's address at the 

 recent opening of the 128th session of the 

 Society of Arts, the later applications of 

 science to the promotion of arts, manufact- 

 ures, and commerce. It could not be said, 

 he remarked, that any new scientific discov- 

 ery or principle has been applied to the 

 steam-engine, which is still our pre-eminent 

 motor, but the principles on which its eco- 

 nomical action depends have been advanced 

 by the application of jacketing for saving 

 steam and the use of higher pressures, with 

 a consequent economy of coal. Available 

 pressures have increased during the last 

 half-century from three and a half pounds 

 to one hundred pounds ; and Mr. Loftus 

 Perkins has engines running with four 

 hundred pounds of pressure above that 

 of the atmosphere, demanding a consump- 

 tion of one and two thirds of a pound of 

 coal per indicated horse-power per hour 

 against two and a half pounds required by 

 engines using a pressure of one hundred 

 pounds. The saving, five sixths of a pound, 

 seems small when expressed in simple fig- 

 ures, but it represents a considerable per- 

 centage, and the difference between running 

 a vessel fourteen days and twenty-one days 

 with the same stock of coal. ^Nevertheless, 

 unless some wholly new and at present un- 

 dreamed-of discovery is made, the steam- 

 engine will have to yield its place to other 

 means of obtaining motive power. The 

 average of British engines do not give forth 

 one twenty-fifth of the energy that may be 

 considered as residing in the fuel they con- 

 sume ; and even if we should obtain a horse- 

 power per hour for as little as one pound 

 of coal, we should still utilize only about a 

 sixth or a fifth of that energy. The opera- 



