5i6 



NATURE 



[April 2. 1896 



■expansion passes through the spaces surrounding the 

 pipe through which the compressed gas is passing to the 

 point of expansion, and so makes this gas, still under 

 pressure, cooler than it was itself while under com- 

 pression. The compressed gas consequently becomes at 

 the point of expansion cooler than that which preceded 

 it, and in its turn follows backwards the course of the 

 still compressed gas, and so makes the latter cooler than 

 before expansion, and therefore also cooler than ever 

 after expansion. This intensification of cooling (always 

 assuming sufficient protection against access of heat from 

 the outside) is only limited by the liquefaction of the gas, 

 the temperature of liquefaction being in the case of 

 oxygen — 180° C. The apparatus exhibited measures 

 28 inches deep by 7 inches in diameter, and when 

 once cooled down, that is, in about half an hour, it 

 yields liquid oxygen at the rate of about seven cubic 

 centimetres in four minutes. No carbonic acid, 

 nitrous oxide, or other artificial cooling agent is 

 •employed either inside or outside the apparatus. 

 With the liquid oxygen obtained, a series of in- 

 teresting experiments were shown, which, however, were 

 not in themselves new, such as the freezing of ether 

 and alcohol, and the pulverisation of india-rubber 

 after cooling. The expanded gas, after leaving the 

 apparatus by the wide tube shown in the diagram, was 

 led back to the suction pipe from which the pump 

 was drawing. The impulse of the pump thus caused 

 rhythmical variation in the pressure of the expanded gas 

 over the surface of the liquid which had collected, and 

 this in its turn produced a rhythmical variation in the 

 small amount of ebullition visible in the liquid. Dr. 

 Hampson's experiments, performed in the presence of a 

 considerable number of representative men, constitute the 

 first complete demonstration in England of the efficiency 

 of the process of self-intensification of cold produced by 

 expansion alone without the aid of extraneous artificial 

 refrigeration. 



It is obvious that the model exhibited admits of modi- 

 fication, both as to size and in some details of arrange- 

 ment ; but this ingenious adaptation of a well-known 

 principle cannot fail to receive important practical 

 apphcations. In the meantime the results already 

 attained have the highest scientific interest. Among the 

 more immediate consequences, we may look for the 

 liquefaction of hydrogen in such quantities as to admit 

 of the more exact study of the physical properties of this 

 ■element in the liquid, and perhaps even in the solid state ; 

 while following upon this, the attainment of, or approxima- 

 tion to, the absolute zero of temperature cannot be far off. 



ANIANUS JEDLIK. 



//^N the 1 2th of last December, a month before having 

 ^^ completed his ninety-sixth year, Anianus Jedlik, 

 who had for half a century been an active labourer in the 

 field of experimental physics, ended his lengthy career at 

 the cloister of the Benedictine Order, in Gyor. 



It was a strange sort of an investigator's life that came 

 to a close with Jedlik's death. We scarcely meet with 

 his name in the international literature of natural sciences, 

 and yet he worked a great deal and wrote a great deal ; 

 but he totally lacked the ambition to obtain the apprecia- 

 tion of foreign fellow-labourers in his branch of learning, 

 for the results attained by him. To him, his researches 

 in the world of physical phenomena afforded in themselves 

 sufficient enjoyment ; and his laboratory work thoroughly 

 satisfied his unpretending nature, which was free from all 

 niesire for fame. 



Stephen Jedlik, who as Benedictine monk adopted 

 for his monastic name that of Anianus, was born on 

 January 11, 1800, at Szimo, in the county of Komirom 

 {Hungary). He frequented the Latin schools at Nagy 



NO. 1379, VOL. 53] 



Szombat and Pozsony. In 181 7 he entered the bonds of 

 the Benedictine Order at Pannonhalma, in 1822 he be- 

 came Doctor of Philosophy, and in 1825 was consecrated 

 officiating priest. 



The talented young priest was intended by his Order 

 for a professor, and so he was employed in teaching 

 natural philosophy successively at Pannonhalma, Gyor, 

 and Pozsony. In 1840 he was appointed Professor of 

 Natural Philosophy at the University of Pest. 



Jedlik's scientific researches extended to various 

 branches of natural philosophy ; nevertheless he turned 

 his attention principally to those physical phenomena 

 which chiefly absorbed the learned men of the time at 

 which he started upon his career, namely, those connected 

 with galvanism and electro-magnetism. 



Within the sphere of these, Jedlik succeeded in making 

 two important discoveries, as we can prove with total 

 certainty. But these discoveries now bear the names of 

 others, who happened to make them independently of 

 Jedlik, and hastened to make the scientific world 

 acquainted with them, while he merely laid them before 

 his own pupils. 



It was in the first years of his professorship — in 1827- 

 1828 — that, upon reading about electro-magnetism in the 

 German periodicals to which he had access, he modified 

 Schweigger's multiplicator in the following manner. He 

 put in the place of the magnetic needle an electro-magnet, 

 and thus, with the aid of a current-commutator, produced 

 permanent rotation. 



Jedlik relates, in his modest manner, that he never 

 came upon any mention of such electro-magnetic rota- 

 tory apparatus in any of the periodicals or works with 

 which he was acquainted, so that he could not but 

 believe that he was their discoverer. But he kept it to 

 himself, as he had repeatedly experienced that descrip- 

 tions of apparatus constructed by him after his own 

 original ideas, already existed elsewhere ; and so he 

 never thought of sending descriptions of the above to 

 any of the foreign scientific periodicals of which he 

 knew. 



Jedlik's other discovery had reference to the funda- 

 mental principle of the dynamo-electric machine. In the 

 collection of the physical department of the University of 

 Budapest, there is a machine of very primitive construc- 

 tion, dating, as it appears, from somewhere about the 

 year i860, and probably the work of some mechanician of 

 Pest, to which are joined directions as to its use in 

 Jedlik's own handwriting. 



In the fourth point of these instructions we find clearly 

 defined the fundamental principle of the dynamo-electric 

 engine, which principle Werner Siemens brought before 

 the Academy of Berlin in 1867, and according to which 

 the magneto-electric currents of augmenting force may 

 be developed by means of mechanical force, with the aid 

 of the slight amount of magnetism contained in ordinary 

 soft iron. 



Jedlik discoursed with great zest upon his investigations 

 at the meetings of natural philosophers and physicians, 

 in whose pubHcations his dissertations are to be found. 

 Several of his treatises appeared in the publications of the 

 Hungarian Academy of Sciences, which elected him its 

 regular member in 1858. 



The topics of some of his more important treatises are 

 as follows: "The Deflection of Beams" (1845); "The 

 Application of the Electro-Magnet in Electro-Dynamic 

 Rotations" (1856); "A Modification of Grove and 

 Bunsen's Battery" (1857); "The Magneto-Motor" 

 (1857) ; "Concatenation of Leyden Jars" (1863), through 

 which peculiar modification he attained a remarkable 

 degree of effect ; " Modification of Fresnel and Pouillet's 

 Interference Apparatus" (1865); "Tubular Electric 

 Collectors" (1867); "Electro-magnetic Undulation 

 Machine" (1868). 



With Jedlik there expired one of the typical figures of 



