154: ANNUAL OF SCIENTIFIC DISCOVERY. 



preceding day. This had gone on regularly for four days ; each day 

 it sank from two to three inches, and only rose half as much ; the 

 fluctuation was in all respects most perfectly regular and symmetri- 

 cal." London Athejucum, Sept. 



NATURE OF THE CANDLE-FLAME. 



3VL VOLGER has recently subjected the flame of the candle to a 

 new analysis. He finds that the so-called flame-bud, a globular blue 

 flammule, is first produced at the summit of the wick ; this is the re- 

 sult of the combustion of carbonic oxide, hydrogen, and carbon, and 

 is surrounded by a reddish violet halo, the xe.il. The increased heat 

 now gives rise to the actual flame, which shoots forth from the ex- 

 panding bud, and is then surrounded at its inferior portion only by 

 the latter. The interior consists of a dark gaseous cone containing 

 the immediate products of the decomposition of the fatty acids, and 

 surrounded by another dark hollow cone, the inner cap. Here we al- 

 ready meet with carbon and hydrogen, which have resulted from the 

 process of decomposition, and we distinguish this cone from the inner 

 one by its yielding soot. The external cap constitutes the most lu- 

 minous portion of the flame, in which the hydrogen is consumed, and 

 the carbon rendered incandescent. The surrounding portion is but 

 slightly luminous, deposits no soot, and in it the carbon and hydrogen 

 are consumed. Liebig's Annual Report. 



ARTIFICIAL MOTHER-OF-PEARL. 



ON the library-table were several curious and beautiful specimens of 

 De la Rue's application of Sir Isaac Newton's thin plates* carved 

 wood, embossed card, plaster of Paris, paper, &c., presenting a me- 

 tallic appearance, but likewise splendid iridal colors, the green pre- 

 dominant. The paper was cut into the form of birds, beetles, &c. ; 

 the varying green shield of the beetle was most natural, and evinced 

 the power of producing any tint or effect required. The material 

 employed for coating the above substances is a colorless varnish, ap- 

 plied by being dropped on water, the specimen to be coated, previous- 

 ly placed in the water, being lifted up against the thin film into which 

 the drop had spread. The colors are due, of course, to the interfer- 

 ence of the luminous rays, the light reflected from the upper in- 

 terfering with that reflected from the under surface ; and upon the ex- 

 tent of the retardation of the luminous waves by such interference, 

 the varieties of colors depend. Mother of-pearl affects light similarly, 

 and thence its lovely hues. White paper, with Mr. De la Rue's 

 coating of varnish, is artificial mother-of-pearl, and a most beautiful 

 representation of it. Proceedings of the Royal Institution. 



THE FRICTION OF WATER. 



MR. R. RAWSON has communicated to the British Association at 

 Birmingham, a paper upon the friction of water, containing the result 



