NATURAL PHILOSOPHY. 145 



IGNEOUS CONDITION OF MATTER. 



In a recent work " On Matter and Ether ; or, the Secret Laivs of 

 Physical Change" by Thomas Birks, M. A., Cambridge (England), 

 1862, the author, in a chapter entitled the "Igneous Condition of 

 Matter," sets forth" the following views : " According to the present 

 theory of the laws of matter, there may be more truth than has latterly 

 been recognized in the old arrangement of the four elements, which 

 placed a fourth region of fire above the solid, liquid, and gaseous con- 

 stituents of our globe. In fact, above the region where the air, though 

 greatly rarefied, is still elastic, there must be a still higher stratum 

 where elasticity has wholly ceased, and where the particles of matter, 

 being very widely separated, condense around them the largest amount 

 of ether. All sensible heat, in the collision or oscillation of neighboring 

 atoms of matter, will thus have disappeared ; but latent heat, in the 

 quantity of condensed ether or repulsive force ready to be developed 

 on the renewed approach of the atoms, will have reached its maximum, 

 and may be capable of producing the most splendid igneous phenomena, 

 like the northern lights, or tropical thunder-storms." 



THE FORMATION OF SMOKE-RINGS. 



Mr. W. B. Tegetemeir, in the London Intellectual Observer, in an 

 article on the production of " smoke-rings," such as are produced by 

 the spontaneous combustion of phosphuretted hydrogen, and by practised 

 tobacco-smokers, describes an interesting method by which these rings 

 can be produced at pleasure by mechanical means. He says, " If six 

 ordinary, oblong cards, each about three inches by four, are taken and 

 the ends folded down, after being partially cut through, so as to leave 

 a central square, as here shown, they may with a 

 Httle dexterity be combined into a very pretty 

 cubical box. Previous to being put together, a 

 circular hole about the size of a fourpenny-piece 

 should be cut in one card. If the box so con- 



structed be filled with any dense smoke, such as that from a tobacco- 

 pipe, or by allowing vapors of hydrochloric acid and ammonia to enter 

 together, smoke-rings, in any number, and at any desired rate of suc- 

 cession, may be caused to issue from the hole in the box, by the slight- 

 est series of gentle taps on one of the sides. Their production in this 

 manner is so facile, and so perfectly under control, that their formation 

 constitutes if the experiment be performed in a room in which the 

 air is perfectly still a very interesting and pretty experiment. 



" So much for the mode of producing these rings. Now let us con- 

 sider their construction. If the reader has ever observed an ascending 

 column of smoke, on a perfectly calm day, he cannot fail to have been 

 struck with the extreme beauty of its form, rising, perhaps, from the 

 summit of one of those tall factory chimneys, now, alas, so smokeless*! 

 It ascends perpendicularly, spreading out as it rises, and gradually as- 

 suming the form of an elongated convolvulus, or, to use a less poetical 

 and more homely comparison, that of a long funnel. This spreading 

 out is due to the resistance of the air, which is greater, being more con- 

 centrated, toward the centre than at the outside. 



" If the reader can imagine the emission of smoke to be intermittent, 

 instead of continuous, it is obvious that this expanding column would be 



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