IX. METEOROLOGY.--Modification of Our Climate.--By JOSEPH WALLACE.--Climate epochs and the probabilities of the present climatic era.--Changes within the records of man The Eruption of Krakatoa.--A graphic description of this catastrophe, involving the lives of 35,000 people X. MILITARY ENGINEERING.--The Military Engineer and His Work.--By Col. W.R. KING.--A Sibley College lecture, treating of the special problems In fortifications, sieges, and the more pacific work of surveys and explorations XI. MINERALOGY.--Natural Sulphide of Gold.--By T.W.T. ATHERTON.--A probable new occurrence of gold XII. NATURAL HISTORY.--The Living Jerboa in the Zoological Garden of Berlin.--A rare rodent from South Africa, one seldom seen alive in captivity.--5 illustrations XIII. NAVAL ENGINEERING.--Twenty-four Knot Steamers.--The possibility of fast ships for long voyages.--The prospects and difficulties XIV. RAILROAD ENGINEERING.--A Steam Street Railway Motor.--A noiseless motor built of steel on trial in Chicago.--1 illustration XV. SANITARY ENGINEERING.--Some Means of Purifying Water.--Different filtering processes and the subsidence treatment of water XVI. TECHNOLOGY.--Action of Caustic Soda on Wood.--By M.H. TAUSS.--Direct experiments on the action of lye on wood at various pressures Burning Brick with Crude Oil Fuel.--The use of petroleum in brick kilns.--Its advantages, cleanliness, and cheapness. Chlorine Gas and Soda by the Electrolytic Process.--The decomposition of common salt solution into chlorine and caustic soda on the commercial scale How Enameled Letters are Made.--The manufacture of separate enameled letters as conducted in London.--5 illustrations How Mechanical Rubber Goods are Made.--Hose, corrugated matting, packing, and jar rings.--Processes of their production * * * * * THE LIVING JERBOA IN THE ZOOLOGICAL GARDEN OF BERLIN. Like other strangely formed quadrupeds, the jerboas are counted among the curiosities of the animal kingdom, and as such are described in natural history; but, nevertheless, there has never been a good exhibition of them, for the simple reason that live jerboas are seldom seen in Europe, as they usually die during the journey hither or soon after their arrival. After some hesitation I decided to purchase a pair that I happened to find mentioned in the price list of Mr. C. Reiche, of Alfeld, as one of the most interesting specimens obtained during his expedition to South Africa the year before; but I, also, found the sensitiveness and delicacy of the jerboa very trying, for the short journey from Alfeld to this city caused the death of the female and reduced her mate to such a condition that when it arrived there seemed little hope that it could ever be utilized for scientific research or artistic life studies.