Mav 4, 138?.] 



♦ KNOWLEDGE 



267 



L- 



AN. lUJi&^RATED ^^ J^ 



MAGAZINEOF^GIENCE "^ 



PLAINLYlf ORDED -fXACTlJf DESCRIBED 



LOXDOX : FRIDAY, MAY \. 1883. 



Contents op No. 79. 



Oo tfaf* Spheroidal Condition of 



Liquids, By Charles Tomlinson. 



F.E.S : 



A Geolopcal Excursion. Br Grant 



Allen : 



" Our Bodies." XI. The Circula- 



tion of the Blood. Bj Dr. Andrew 



Wilson. F.R S.E., ic i 



How to Use Our Eyes. V. By John 



Brownini;, K.K.A'.S I 



A Dream of Infmity. By De Quincey, 



after Richter J 



Death of Worlds. Bt R. A. Proctor ; 



The Crystal PaUoc Electric and Gas 

 Eihibition. Final notice, (lllm.) : 



The Moon in a Three-inch Tele- 

 scope. HUu>.) By F.R.A.8. ... ! 



Reviews : Practical Oeoraetry i 



CoERBSPOKPBNrR ; — Comets* IVuls 

 — Tide and Weather — The Great 



Pyramid, Sc : 



1 Our Mathematical Column 1 



Our Whist Column : 



I Our Chess Coltunn '. 



ON THE SPHEROID.\L CONDITION 

 OF LIQUIDS. 



By Cuahles Tomlinson, F.E.S. 



1HAVE road, with considerable interest, Professor 

 Barrett's note on this subject (Vol. I., p. l.'iO). 



On several occasions, during a long scientific life, I have 

 engaged in researches thereon ; and it may be interesting 

 to recapitulate the various phenomena, leaving the task of 

 deciding wliich of them fall under the new theory, and 

 which belong to the old, to the competent judgment of Mr. 

 Stoney and Professor Barrett. 



So long ago as the year 1838, my " Students' Manual 

 of Natural Philosophy " contained an account of my first 

 researches. I quote, with some abridgment, from pp. 5.")3 

 et seq. of that work. 



After describing an experiment by Professor Baden 

 Powell on the so-called repulsion of heat, in which 

 Newton's rings disappear on applying the flame of a spirit- 

 Ikmp to the lower lens, the text proceeds thus : — "There 

 is another striking phenomenon, discovered by Leidenfrost 

 in 17.")G, which seems to prove the existence of a repulsive 

 force between heated bodies, which force augments with 

 their temperature. If a polished metal vessel, such as a 

 platinum crucible, be raised to a red or white heat, and 

 several drops of water be allowed to fall into it, they unite 

 into a globule, which spins rapidly round witliout ebulli- 

 tion, and evaporation is slow in proportion as the tem- 

 perature of the vessel is high. It is necessary to the 

 SDCcess of this experiment that the globule, whether 

 bom calorific repulsion, or any other cause, be not 

 in contact with the heated metal ; and accordingly 

 we find that if the vessel be removed from tlic 

 source of heat, and allowed to cool down to a certain 

 point, the water flashes into steam by coming into 

 contact with the heated metal. I find that these pheno- 

 mena apply also to ether, alcohol, and many saline solu- 

 tions, but not to fixed oils. I have also varied the ex- 

 periment by employing a fixed oil at 4.'')0° or 500° 

 Fahr., instead of the heated metal. When oil of turpen- 

 tme is dropped upon its surface, it forms a disc, with a 



perfectly well-defined edge ; the disc rotates rapidly in a 

 horizontal plane, and soon disappears by evaporation. If 

 s(>veral drops of etlier be placed upon the heated oil, they 

 unite and form one largo globule, which rotates rapidly, and 

 moves swiftly over the surface. If now a drop of water be 

 placed upon the heated oil, or rather be gently dolivored 

 to it from the end of a pipette, it forms a similar figure 

 to the ether, and bcha\es like it ; but soon the two 

 globules coalesce, and tlie compound drop moves and 

 rotates as before ; or it may sink below tlie surface of 

 the oil, burst into vapour, and scatter the oil ; hence 

 caution is required in conducting this experiment. In 

 some cases, however, the globule may be thrown up again 

 to the surface, and continue to rotate as before. 



" It is remarkable that a drop of so volatile a li(iuid as 

 ether should rest upon the hot oil without evaporating 

 much more quickly than a similar drop would do on a 

 surface at the ordinary temperature of the air ; also that 

 water, which is so much denser than the hot oil, should 

 rest upon it, and move about with great rapidity. By 

 colouring the water with ink it will be seen that the 

 ether completely envelopes the aqueous globule, and even 

 increases its duration. Alcohol, wood spirit, naphtha, and 

 bisulphide of carbon form globules on the surface of the 

 hot oil, and behave in the same manner as the ether. 

 Ether also forms a rotating globule on the surface of hot 

 water and mercury. If sulphuric acid be heated to about 

 •100°, and ether be placed on its surface, it forms 

 globules which dart about with great rapidity. Alcohol 

 also forms gloliules, but naphtha and turpentine form 

 discs, wliich soon disappear with decomposition." 



In 1845, I was introduced to M. Boutigny, in the labo- 

 ratory of King's College, London, where in the presence 

 of Professor Miller, and some other scientific friends, he 

 showed the experiments whicli ho had shortly before 

 described in a small pamphlet. He also described his 

 results in a lecture at the Royal Institution, which I 

 attended. 



M. Ganot attributes to Boutigny the invention of the 

 term, " spheroidal state of liquids," but the term is much 

 older than his researclie.s. In conversing with him, he 

 freely admitted that I had anticipated him in many of his 

 results. He stated that water in the hot crucible evapo- 

 rates fifty times more slowly than if boiling, and that the 

 higher the boiling point of the liquid, the hotter must be 

 the metal ; that any liquid in the spheroidal state is 

 always below the temperature of its boiling point. Water, 

 for example, is at 95.5^0. ; alcohol at 75.5" ; ether at 34' ; 

 sulphurous acid at — 10,.")" ; but that the vapour disengaged 

 is higher in temperature. The lowest temperature of 

 platinum necessary to the production of the spheroidal 

 state is for water 171° C, for alcohol 131°, and for ether 

 Gl°, If boiling water be put into the heated crucible, its 

 temperature immediately falls 4° or 5°. Anhydrous sul- 

 phurous acid boils at — 10° C, and in the red-hot crucible 

 some degrees below that point, so that when water is 

 added it instantly congeals, and we have the singular 

 spectacle of a lump of ice being formed in, and turned out 

 of, a red-hot crucible. I was so fortunate as to be present 

 when Faraday first exhil)ited the still more singular spec- 

 tacle of freezing mercury in a bath of solid carbonic acid 

 in ether, contained in a red-hot crucible. 



Boutigny also showed that a liquid in the spheroidal state 

 is not in contact with the hot metal. For this purpose a 

 silver plate was made h''^rizontal, and heated. Water 

 blackened with ink was dropped upon it, and, on directing 

 the eye through the space between the globule and the 

 heated surface, the flame of a candle could be seen on the 

 other side, Poggendorfl" established the same fact more 



