554 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



flame. The flow of gas and admission of the air are both 

 regulated by collars at the end of a horizontal handle, so 

 that the tip of the jet is not liable to injury by liquids, etc., 

 accidentally falling into the lamp ; it is, besides, also supplied 

 with a curved attachment for the end of the lamp tube, with 

 which it is impossible for fused substances to run into the 

 lamp. By a flat attachment a broad, narrow flame is afford- 

 ed, suitable for heating uniformly a considerable length of 

 a glass tube, as in bending it, and by rose and gauze-burner 

 attachments, any desired distribution of the flame can be 

 made; while a tripod, adapted to the support of capsules, 

 flasks, etc., which can be attached to the cast-iron foot of the 

 lamp, and be moved with it, completes its character as a per- 

 fect gas-stove. 5 C, XXIX., 1874, 231. 



DE LA BASTIE's HARD OR TEMPERED GLASS. 



A French engineer, M. Francois de la Bastie, after a long 

 series of experiments, has discovered a simple means of ren- 

 dering glass practically unbrittle, and at the same time of 

 preserving its transparency, which it is understood he in- 

 tends to utilize by commencing the manufacture of articles 

 of toughened glass upon an extensive scale. The process of 

 conversion is, in the main, a very simple one. In general 

 terms, it consists in heating the glass to a certain tempera- 

 ture, and plunging it, while yet hot, in a heated bath of some 

 oleaginous compound. There are, it is represented, many con- 

 ditions and details upon which the success of the operation de- 

 pends. Of these, the temperature of the glass and the nature 

 and temperature of the oil-bath are named as the most im- 

 portant. These and other matters of detail, report says, M. 

 De la Bastie has satisfactorily solved, and has constructed 

 furnaces and apparatus with which his tempering process 

 can be carried into effect without risk or failure. The time 

 actually employed in the tempering is but nominal, the ar- 

 ticles, heated to the required temperature, being simply in- 

 serted into the bath and instantly withdrawn. The cost of 

 the operation is likewise represented to be small. 



M. De la Bastie's experiments, it is said, were first made 

 with the object of effecting the toughening of glass by com- 

 pression, but without success ; for although this principle 

 holds good in practice with the metals, and especially with 



