April I St, 1887.] 



SCIENTIFIC NEWS. 



27 



some remarkable results in conjunction with M. Fail, whose 

 recent death is now so much deplored. Two methods had 

 then been in operation, viz. : ist, The fusion at a white-red 

 heat of a mixture of alumina and minium with a small 

 quantity of bichromate of potash; and, 2nd, The treat- 

 ment at the same temperature of alumina, to which were 

 added baric fluoride and a very little chromic acid. In both 

 characteristic crystals were obtained, but they had a 

 tendency to be laminated, and were too small for cutting. 

 Since then M. Fremy has endeavoured to obtain still better 

 results, and this time has resumed his experiments with the 

 co-operation of M. Verneuil. The alumina was mixed with 

 calcic fluoride, and was subjected to the action of heat, the 

 crucible being made of platinum or alumina. In every case 

 the crystallization sought for was obtained, and M. Fremy 

 does not hide the astonishment he felt on seeing large 

 masses of alumina transformed into crystals by a trifling 

 addition of the fluoride. Diminishing gradually the propor- 

 tion of the latter, he finally succeeded with one part of 

 fluoride mixed with twelve parts of alumina. He even suc- 

 ceeded in crystallising the oxide on heating it in a crucible 

 containing some fluoride, but separated from it by a finely- 

 perforated partition. Nothing could justify more thoroughly 

 the previous opinions of such authorities as M. H. Sainte- 

 Claire Deville and M. Debray, as to the important influence 

 of fluorides in the formation of minerals ; and theoretical 

 geology as well as practical mineralogy will both gain by 

 these new experiments of M. Fremj'. 



The Air Brush is a new appliance which has recentlj' 

 been introduced in America. It is a tool for applying 

 liquid pigments to paper or other surfaces in the production 

 of pictures. It operates in the following manner. The 

 artist supplies liquid colour from a brush to a spoon-like 

 receiver. Through this liquid a fine needle darts rapidly 

 backwards and forwards, its wetted point being carried 

 beyond the edge of the spoon. A strong current of air 

 directed on the point of the needle blows the colour in 

 fine spray against the paper. When the point is held near 

 the paper a fine line of colour is drawn, and this is widened 

 by drawing the point further oif. The greater or less length 

 of the stroke of the needle, as well as the current of com- 

 pressed air playing on it, are under control of the artist's 

 thumb and foot, the latter being used to work the bellows 

 supplying the air. The instrument has been submitted to the 

 Sub-Committee on Science and Arts of the Franklin Insti- 

 tute, who have reported that it is an acquisition of rare 

 value in the hands of an accomplished draughtsman, and 

 that it is worthy of the highest award the Franklin Institute 

 can bestow. The Air Brush Manufacturing Company of 

 Rockford, Illinois, U.S., are the makers of this novel in- 

 strument. 



A New Disinfectant for Sewage. — Mr. Carl Liesenberg 

 has recently taken out a patent in Germany for the purifi- 

 cation of refuse water by means of sodium ferrate. This 



product is obtained in a furnace by melting crude soda with 

 suitable iron ores, finely powdered. When Bauxite clay 

 ironstone and cognate ores are used, a sodium aluminate is 

 also formed, which is supposed to be of no value for the 

 purification of the water. Neither is it suitable for a mordant, 

 for artificial stones, or for glass manufacture, as, for these 

 purposes, the sodium aluminate must be perfectly free from 

 iron, which is not the case in the bye-product formed by the 

 patented process. The water to be purified is treated and 

 cleared with lime in the ordinary way ; then the sodium 

 ferrate (Na^ Fe^ Oj) is added, and this yields with the 

 water ferric hydrate and sodic hydrate. The ferric hydrate 

 forms the well-known reddish flakes, which rapidly settle 

 and carry down with them any suspended matter. 



Manganese Steel is a new alloy which is being intro- 

 duced by Messrs. Pfeil and Co., of Clerkenwell. Some re- 

 markable tests with this material have recently been made 

 before a party of gentlemen interested in metallurgical 

 operations, and the results show that this steel possesses 

 unusual qualities. Bolts were bent over by hammering 

 through about 120 degrees in the threaded part without 

 showing the least sign of distress, and nuts were hammered 

 down until the screwed way was nearly closed, with 

 similar results. The necks of the bolts were also bent 120 

 degrees and were only broken through by being hammered 

 back again, the metal showing an excellent fracture. Bolts 

 and nuts of this steel are now being used in the Royal 

 dockyards and in the carriage department at the Royal 

 Arsenal, Woolwich. 



The Growth of Children. — For three years Mr. M. 

 Hansen, the director of the Deaf and Dumb Institution at 

 Copenhagen, has weighed and measured daily all his pupils, 

 and he reports having made the following observations : — 

 The growth of children is not regular or progressive, but 

 proceeds at intervals after rest. Their weight increases only 

 after periods of equilibrium. When the weight increases 

 the height remains nearly stationary, and vice versa. The 

 maximum increase in height corresponds with a period of 

 minimum increase of weight. These variations are also 

 affected by the seasons, thus during the autumn and the 

 beginning of winter the child increases in weight, but its 

 height is hardly changed. On the other hand, during the 

 spring the height is appreciably increased, but there is no 

 addition to the weight. 



A Long Hydraulic Lift. — The Winchester House Com- 

 pany, of Old Broad-street, City, has just started a hydraulic 

 passenger-lift of exceptional size. It has a total travel of 

 90 feet, and a solid steel ram measuring 5| in. in diameter 

 by about 95 feet in length. Two other lifts in the building 

 have a travel of 80 feet each, and all work at a speed of 

 250 feet per minute. They are on Stevens' and Major's 

 hydraulic balance system, and are made by Messrs. Archi- 

 bald Smith and Stevens. 



