2IO MODERN CHEIMTSTRY. 



gained for liim Prof. W. ( Jstwald's commendation that they were 

 the work of " a quite unusual scientific imagination, taking the 

 word in its best sense." So it goes without saying that in this 

 book all who have followed recent scientific progress will find 

 much to interest, and not a little to profit by. While the book 

 is not altogether free from faults, it is stored with valuable 

 information on-a great variety of topics seldom brought before 

 the general reader, including the Electronic theory ; the proto- 

 elements ; Fournier d'Albe's speculations; the seepage of the 

 ocean into the earth's crust ; Arrheniu.s' theory of the inter- 

 planetary spread of life ; the swift succession of events within 

 the atoms; the Xitrogen problem; the astonishing complexity of 

 carbon compounds, illustrated by the resemblance between a 

 single molecule of cellulose and the entire visible celestial 

 universe ; the increase of atmospheric carbon dioxide and con- 

 sequent amelioration of climate ; and numerous other aspects of 

 chemical science, |)ure as well as applied. Dr. Martin occu- 

 pies himself in his opening chapter with the theories of matter, 

 the mystery of its constitution, and its relation to the Ether, 

 niie underworld of atoms is next considered, and, amongst other 

 associated subjects, molecular motion in its inconceivable swift- 

 ness is dealt with. A short reference to the all but incredible 

 speeds of the particles which build up the atoms themselves — 

 speeds exceeding 100,000 miles per second — leads on to an ex- 

 planation of the principle and functions of the ultra-microscope, 

 that instrument by means of wdiich it is asserted that the larger 

 molecules, those of albumen, for example, have actually been 

 rendered directly visible. The evolution of the elements — a 

 phrase now received into common use — forms the text of the 

 third chapter, and from this the author gradually passes on to 

 stellar chemistry, with the inevitable glance at the future destinies 

 of the universe, and at the compensational forces under whose 

 laws it moves onward. By the ladder of analogy the descent 

 from the infinitely great to the infinitesimally small becomes 

 easy, and so. from stellar systems, we are led on — following the 

 lead of Mendeleef and Sir George Darwin — to the consideration 

 of atomic suns with electronic satellites, grazing impacts, like 

 those which Prof. A. W. Bickerton has depicted with respect to 

 crossing celestial bodies, serving as detailed illustrations to ex- 

 plain the course of events in chemical reactions between atoms — 

 solar .systems in ultra-micro-miniature as they are. In the next 

 ten chapters of the book, water, hydrogen, air, oxygen, nitrogen, 

 carbon, carbon dioxide, silicon, sulphur, and phosphorus are 

 successively treated, and, although much of the information con- 

 tained in these chapters is far from new, the facts are dealt 

 with dififerently from the manner usual to chemical text-books. 

 One instance of this is the statement, given on the authority 

 of Erdmann (Lehrbuch der anorganischen Chemie) and Sir 

 James Dewar (Presidential address to the British Association, 

 Belfast. 1002), as an observed fact, supported by theoretical 



