THE PROGRESS OE SCIENCE. 



223 



ber of the British Parliament. Milne- 

 Edwards published important researches 

 in paleontology and in zoology, espe- 

 cially in relation to birds, and was at 

 the time of his death professor of zool- 

 ogy at Paris and director of the Jardin 

 des Plantes. 



In the deaths of the Duke of Argyll 

 and Prof. St. George Mivart, Great Brit- 

 ain loses two men of a type more com- 

 mon there than in the United States, 

 Argyll was a man of great wealth, 

 whose interests in science were only sec- 

 ondary, but who did much directly and 

 indirectly for its advancement. His 

 work, 'The Reign of Law,' published 

 some twenty-five years ago, has been 

 widely read, and he is the author of 

 many books and articles concerned with 

 the natural sciences. Mivart, although 

 trained as a barrister, became perhaps 

 a professional man of science, but he 

 never occupied a regular university posi- 

 tion. He published numerous contribu- 

 tions to comparative anatomy and zool- 

 ogy, but is perhaps best known for 

 books and articles on general scientific 

 subjects. Just before his death, it will 

 be remembered, he was excommunicated 

 from the Roman Catholic Church owing 

 to articles which were supposed not to 

 be in conformity with its tenets. Both 

 Argyll and Mivart represented an atti- 

 tude towards the doctrine of evolution 

 which may be regarded as now practi- 

 cally extinct. 



Two lectures have been recently de- 

 livered by Prof. James Dewar at the 

 Royal Institution on the subject of 

 liquid and solid hydrogen. These lec- 

 tures have been illustrated by experi- 

 ments and have attracted the attention 

 of the most distinguished chemists and 

 physicists of England. It is easy to un- 

 derstand such interest in the subject 

 when we consider that even Clerk Max- 

 well thought it improbable that hydro- 

 gen would ever be liquified, and yet 

 Dewar was able to exhibit not only 

 liquid, but solid, hydrogen to his audi- 

 ence. Briefly recapitulated, the steps in 



the condensation of what were formerly 

 called the permanent gases are these : in 

 1878 Cailletet, in Paris, and Pictet, at 

 Geneva, by suddenly expanding gases 

 which had been compressed to a high 

 degree and cooled to a low temperature, 

 succeeded in obtaining these gases in the 

 shape of a mist or of a transitory liquid 

 jet. In 1884 Wroblewski and Olszewski 

 at Crakow obtained oxygen and nitro- 

 gen as static liquids. By expanding 

 hydrogen from a compression of 190 at- 

 mospheres in a vessel cooled by liquid 

 air evaporating under diminished pres- 

 sure, this gas was obtained as a mist 

 or momentary froth, though it was af- 

 firmed by Olszewski that he observed 

 the liquid hydrogen in colorless drops 

 and as a liquid running down the sides 

 of the tube. In May, 1898, Dewar ob- 

 tained hydrogen as a static liquid by al- 

 lowing compressed hydrogen, cooled in 

 a bath of boiling air, to escape rapidly 

 at a jet, the liquid hydrogen being col- 

 lected in a doubly isolated vacuum ves- 

 sel. This liquid hydrogen is a colorless 

 liquid, with a specific gravity of 0.07 

 or less than one sixth the weight of 

 liquid marsh gas, the lightest liquid 

 hitherto known. This is better realized 

 by saying that while one gram of water 

 has the volume of one cubic centimeter, 

 one gram of liquid hydrogen has a vol- 

 ume of over 14 c. c. The boiling point 

 of hydrogen is — 252° C. or 21° above 

 the absolute zero, and by boiling in a 

 vacuum the temperature of 15° can be 

 obtained. Very recently by slowly 

 evaporating, very perfectly isolated 

 liquid hydrogen, solid hydrogen was ob- 

 tained by Dewar as a white mass of 

 solidified form, of the lowest tempera- 

 ture ever obtained, — 258° C. 



Among the most suggestive results 

 obtained through recent work in experi- 

 mental embryology are those of Prof. 

 Jacques Loeb, of the University of Chi- 

 cago, on the chemical fertilization of the 

 eggs of sea-urchins without participa- 

 tion of the male element. There has for 

 some time been reason to suspect that 

 cell-division, both in tissue cells and in 



