286 



THE POPULAR SCIENCE MONTHLY. 



as the assimilative faculty of her pupil:;. In 

 all object-lessons, various specimens of the 

 object should be produced for examination 

 and description ; the little ones themselves 

 must do the main part of the latter under 

 the teacher's guidance, for these lessons are 

 not only to enable the children to form new 

 ideas, but they are also intended to train 

 them in giving expression to such ideas. 

 The teacher must make good use of the 

 blackboard, and should practice drawing 

 objects, so that she may illustrate with fa- 

 cility and precision any particular point of 

 her lesson which can be so illustrated. All 

 the materials, pictures, diagrams, etc., which 

 the teacher provides from time to time 

 should have their place in the school mu- 

 seum ready for future needs, and the chil- 

 dren should be encouraged to bring contri- 

 butions to such a museum, particularly such 

 as the lessons they receive may suggest." 



Artificial Prodnction of Minerals. — Ac- 

 cording to M. Friedel, of the French Asso- 

 ciation, experimentation in the artificial pro- 

 duction of minerals was suggested by the 

 observation of the crystalline products acci- 

 dentally formed in the metallurgic furnaces. 

 Mitscherlich and Berthier took it up, and it 

 has been advanced by a considerable num- 

 ber of experimenters. MM. Fouque and 

 Michel L6vy, by melting certain silicates 

 and then exposing the vitreous mass to a 

 lower temperature than that of fusion, have 

 reproduced the identical minerals formed in 

 the eruptive rocks, including the anorthite 

 and labradorite feldspars, amphigene, py- 

 roxene, peridote, and magnetic iron. While 

 the granites have not been produced as 

 such, their constituents — quartz and ortho- 

 clase and albite feldspars — have been ob- 

 tained in crystals. The first essays at re- 

 producing the zeolite groups of minerals 

 have been made by De Pchulten, by heating 

 the silicate of soda in tubes of aluminous 

 glass. Spinel and corundum, among pre- 

 cious stones, were long ago produced by 

 Gaudin, Ebelman, H. Sainte-Claire Deville, 

 and Caron ; and MM. Fr(!'my and Fell have 

 more recently prepared the ruby in large 

 crystalline masses, which possess all the 

 properties of the natural mineral except 

 the susceptibility for cutting. A new ad- 

 vance seems to have been made in produc- 



ing rubies, for artificial stones of fair di- 

 mensions have been met with in the trade, 

 which, though not as bright and transparent 

 as the natural gems, have their hardness, 

 density, and optical properties. The dia- 

 mond alone appears to have so far resisted 

 all attempts at reproduction. 



Somnambalism. — The phenomena of 

 somnambulism and their connection with 

 the nerve-centers have not been satisfac- 

 torily accounted for. They probably de- 

 pend primarily, says the " Lancet," upon a 

 directing impulse of sensory origin. Some 

 of our actions often become by practice so 

 nearly automatic that partial sleep or stupor 

 does not arrest their unconscious perform- 

 ance. In somnambulism the intellect and 

 the controlling will are torpid, while the 

 sensori-motor man whom they should gov- 

 ern is awake and active. As in dreams the 

 intelligent sensorium is alone drowsily ac- 

 tive, with possibly a noticeable tendency 

 to restless movement, so there may be oth- 

 er states of dreaming, in which the centers 

 of motion are stimulated to a more power- 

 ful but unconscious action. Partial coun- 

 teractives to somnambulism may be found 

 in throwing off worries, and in the proper 

 regulation of evening meals. 



British Colonial Wines. — Among the 

 features of the Indian and Colonial Exhi- 

 bition held last year in London, was the de- 

 partment of colonial wines, in which the 

 Australian wines played a prominent part. 

 The soil, climate, and other Australian con- 

 ditions differing from those to which Euro- 

 pean vines are subject, have stamped these 

 wines with an individuality, in consequence 

 of which they can never become exact sub- 

 stitutes for those of Europe. The lighter 

 qualities of the Australian wines are be- 

 lieved, however, to be suited for consump- 

 tion in England, where the commoner wines 

 of France might be found too cold and thin 

 for ordinary use. The phylloxera was dis- 

 covered in Australian vineyards in 1877, but 

 was checked in a very short time by the ap- 

 plication of summary and effective measures. 

 The Cape of Good Hope is capable of pro- 

 ducing immense quantities of wine per acre, 

 amounting in some vineyards to niue times 

 the average in France, and four times in 



