POPULAR MISCELLANY. 



425 



The products of some of the shops would 

 almost deceive an expert ; but the test of 

 hardness is still infallible. The beautiful 

 " French paste," from which imitation dia- 

 monds are made, is a kind of glass with a 

 mixture of oxide of lead. The more of the 

 latter, the brighter the stone, but also the 

 softer, and this is a serious defect. The 

 imitation stones are now so perfectly made, 

 and are so satisfactory to those who are not 

 very particular, that their influence begins 

 to be felt in the market for real stones. By 

 careful selection of the ingredients and skill 

 and attention in manipulation, the luster, 

 color, fire, and water of the choicest stones 

 are, to the eyes of laymen, fully reproduced. 

 There are a few delicacies of color that can 

 not be perfectly given, for they depend on 

 some undiscoverable peculiarities of molecu- 

 lar arrangement and not on chemical com- 

 position, but the persons who are to buy 

 the stones know nothing of that. Yet Si- 

 dot, a French chemist, has nearly reproduced 

 these peculiarities, including the dichroism 

 of the sapphire, with a composition of which 

 the base is phosphate of lime. Two other 

 French chemists, Fremy and Feil, have pro- 

 duced rubies and sapphires having the same 

 composition with the genuine stones, and 

 nearly equal hardness. 



The Futnre of Political Economy. — Mr. 



John Biddulph Martin, president, said, in 

 the British Association's section of Econom- 

 ic Science and Statistics, that we need not 

 despair of the future of political economy 

 because its teaching, based too often on a 

 priori reasoning, and too little on the expe- 

 rience of history, does not always square 

 with the judgments of men. May we not 

 claim that political economy has rather 

 taken up wider ground, than that it has 

 abandoned many of its outworks ? It is no 

 reproach to economic science to have done 

 so ; to have recognized as matters within its 

 proper scope considerations that the older 

 economists, concerning themselves with 

 wealth in its narrow sense, as the summum 

 bonum y and with the desire for its acquisi- 

 tion as the one mainspring of human action, 

 would have regarded as sentimental and 

 philanthropic. Humanity is many-sided, its 

 units do not lend themselves to grouping or 

 combination with the precision of mathe- 



matical symbols, and the experiments of tho 

 social philosopher are subject to disturb- 

 ances unknown in the laboratory of the 

 chemist. It is at this point that the statis- 

 tical method comes in as an inseparable ally 

 of economic speculation. The speaker pro- 

 ceeded to a fuller review of the merits and 

 faults of the statistical method, and then 

 dwelt at considerable length on the tendency 

 of men to accumulate in cities. 



Australian Paradoxes. — In connection 

 with the recent determination of the ovipa- 

 rous character of the monotremes, " Nature " 

 republishes the following list of the para- 

 doxes of Australia from a work published 

 in 1S32 : " But this is New Holland, where 

 it is summer with us when it is winter in 

 Europe, and vice versa ; where the barom- 

 eter rises before bad weather, and falls be- 

 fore good ; where the north is the hot wind, 

 and the south the cold ; where the humblest 

 house is fitted up with cedar; where the 

 fields are fenced with mahogany, and myr- 

 tle-trees are burned for fire-wood ; where 

 the swans are black and the eagles white ; 

 where the kangaroo, an animal between the 

 squirrel and the deer, has five claws on its 

 fore-paws and three talons on its hind-legs, 

 like a bird, and yet hops on its tail ; where 

 the mole lays eggs, and has a duck's bill ; 

 where there is a bird with a broom in its 

 mouth instead of a tongue ; where there is 

 a fish, one half belonging to the genus Raja 

 and the other half to that of Sgualus ; 

 where the pears are made of wood, with 

 the stalk at the broader end ; and where 

 the cherry grows with the stone on the out- 

 side." 



A New Incandescent Gas-light. — Mr. 



Conrad W. Cooke described, in the British 

 Association, the Welsbach system of gas- 

 lighting by incandescence. It consists in 

 impregnating fabrics of cotton or other 

 substances, made into the form of a cylin- 

 drical hood or mantle, with a compound 

 liquid composed of solutions of zirconia 

 and oxide of lanthanum (or with solutions 

 of zirconia with oxides of lanthanum and 

 yttrium). This mantle, under the influence 

 of a gas-flame, is converted into a highly 

 refractory material capable of withstanding 

 the highest temperature that can be ob- 



