70 ANNUAL OF SCIENTIFIC DISCOVERY. 



ever calls them, are easily and clieapl}' made. A piece of fused 

 loracic acid, the size of a walnut, from which the watvr of crys- 

 tallization has been expellid, is heated to rcnlness in chhn'ine, or 

 has dissolved in it while hot a small quantity of common salt, 

 care b^ing- taken that there is not sullicint soda — IG percent. — to 

 convert the boracic acid into borax, which would spoil the eifect. 

 The red-hot lump of boracic aeid thus charged is blown with a'eom- 

 mon glass-blower's tube into a thin glass ball or bull), about the 

 size of a small hand-lamp shade, and the gasophaner is ready for 

 use. When hrst made, the glass is clear, with beautiful irrides- 

 cent colors, due partly to the tliinness of its sides; but left for a 

 time, shorter or longer, according to the amount of moisture in 

 the atmosphere, in normal breathing air, it becomes covered or 

 clouded Avith a light-blue film (due chiefly to the carbonic aeid 

 gas of atmosphere), which, combined with the irridescent colors 

 beneath, has an oi^aline or pearly lustre. On bringing the 

 clouded gasophaner carefully to the flame of a spn'it-lamp, this 

 film instantaneously vanislies, leaving the glass of that jDart again 

 clear and shining. The delicacy of this test is so great that, 

 although by l)re:ithing on the newly-made gas the film may be 

 much more rapidly formed than by mere exposure to the atmos- 

 phere, an approach to the spirit-lamp flame will no longer drive 

 off the carbon:ited compound formed, on account of the imi)uro 

 gases contained in bre;ith. At the sam.: time, carbonates thus 

 form d from the breath of a child, or of an extrem(dy healthy 

 person, vanish precisely as the aerial ones do on application of 

 gentle heat. Ileld over a solution of ammonia, the air carbonate 

 will not form, except on the upper part, where the ammoniacal 

 gas h:is less action; but if held so that the breath may mix Avith 

 the ammoniacal iras, a thick white cloud of carbonate of ammo- 

 nia without opaline lustre covers the gasophaner. This cannot 

 be driven off' by heat, but froths up on an approach being made 

 to the lamp flame. l>ut the most remarkable indication given by 

 the gasophaner is when it is held over a solution of sulphuretted 

 hydrogen. The gasophaner immediately Ijccomes pitted, as it 

 vv'cre, with small-j^ox on the surface next the gas ; and these 

 spots, on being examined with a microscope, are found to be 

 round, radiated crystals, the centre or nucleus of which soon 

 bursts into a hole. They are white by transmitted, and dark 

 brown l)y reflected, licrht. Nitride of boron gave exactly similar 

 ciystals as the chloride, and so did pure boracic acid. These 

 crystals, therefore, are presumed to indicate a combination of 

 boron with hydrogen, a fact hitherto imlaiown to chemists. The 

 gasophaner can be relieatcd and reblown as often as requii'ed. 



UNIFOr.MITY OF WEIGHTS AND COINS. 



Pi-ofcfisor Leone Levi, at the meeting of the British Association, 

 4'ead the report of the committee on " Uniformity of Weights and 

 Coins in the interest of Science.'" The report commenced by stating 

 that coubidcrable progress has been made during the year in the 



