POPULAR MISCELLANY, 



427 



and plants in detail, and as illustrating evo- 

 lution, is in no sense a part of geography. 

 Geography and history are related in their 

 elementary stages, but diverge in their high- 

 er stages. The geographer must furnish to 

 the historian the ideas and facts in science 

 which he requires, and must go to the his- 

 torian for the verification of the relations 

 which he suggests. The body of laws gov- 

 erning those relations, which might in time 

 be evolved, would render possible the writ- 

 ing of much " prehistoric " history. Mr. 

 Green's " Making of England " is largely a 

 deduction from geographical conditions of 

 what must have been the course of history. 



Water-Sponts in the itiantic. — Many in- 

 teresting reports in regard to water-spouts, 

 sighted by masters of vessels during Janu- 

 ary and February oif the Atlantic coast of 

 the United States, have been received by the 

 Hydrographic Office of the Navy Depart- 

 ment. Water-spouts are a special class of 

 whirlwinds, and their manner of formation 

 is described as follows in a supplement to 

 the "Pilot Chart of the North Atlantic 

 Ocean" for March: "A layer of warm, 

 moist air at the surface of the ocean hap- 

 pens to have above it a layer of cooler, drier 

 air. This condition of things is one of un- 

 stable equilibrium, and sooner or later the 

 warm, light air at the surface rises through 

 the cooler and heavier air above. This pro- 

 cess sometimes takes place gradually over 

 large areas, but at other times it is more 

 local, and there seems to be formed in the 

 upper layer a break or opening through 

 which the air of the lower layer begins to 

 drain upward, as through a funnel. Under 

 favorable conditions — that is, when the dif- 

 ferences of temperature and moisture and 

 the supply of warm, moist air at the surface 

 are great — this action becomes very intense, 

 and this intensity is still further increased 

 by the fact that as the air i-ises its moisture 

 is condensed, the latent heat thus liberated 

 adding to the energy of the rising column of 

 air. Now, as this surface air rushes in and 

 escapes upward through the opening thus 

 formed in the upper layer, it takes up a ro- 

 tary or whirling motion, the velocity of which 

 increases toward the center or axis of the 

 funnel, and a suction or partial vacuum is 

 created, as indicated by the low reading of 



the barometer at the center of a cyclone or 

 whirlwind. When a whirlwind is thus formed 

 over the ocean, water is often drawn up the 

 center of the whirl some distance, owing to 

 the suction created, and at the same time the 

 moisture in the air is condensed as it rises, 

 so that the name ' water-spout ' is very appli- 

 cable. Indeed, sometimes a spout will burst 

 over a vessel and flood her decks with water, 

 as a cloud-burst does a mountain-side. When 

 a spout is forming, its upper portion is often 

 visible first, seeming to grow downward from 

 the clouds. By observing carefully with a 

 telescope, however, it will be seen that the 

 motion in the column itself is upward, al- 

 though the moisture in the air which is rising 

 is condensed lower and lower down, thus 

 rendering the whirl visible lower down con- 

 tinually, and making it appear to be actually 

 descending." That part of the North At- 

 lantic from Cuba to the latitude of Phila- 

 delphia, and from the Atlantic coast of the 

 United States to the Bermudas, is pre-emi- 

 nently a region where water-spouts are liable 

 to occur, owing largely to the warm, moist 

 air lying upon the Gulf Stream, and the 

 cool, dry air brought over it by the north- 

 westerly winds from off the coast. Most of 

 the water-spouts referred to were seen within 

 this region. The Office wishes to receive 

 many full and accurate reports of such ma- 

 rine phenomena, in order that knowledge of 

 them may be increased. The most impor- 

 tant observations regarding a water-spout are 

 the temperature of the air and water, the 

 reading of the barometer, direction and force 

 of the wind, and the changes which take 

 place in each while the spout lasts ; also, 

 the direction of rotation of the whirl, and an 

 estimate of its size, character, and changes of 

 form, with, if possible, photographs or sketch- 

 es, however rough, of its appearance at the 

 various stages of its formation and progress. 



An Ancient Human Foot-print, — The dis- 

 covery of human foot-prints in volcanic rocks 

 near the shore of Lake Managua, Nicaragua, 

 under circumstances which seemed to assign 

 them a remote antiquity, has been announced 

 for several years. Dr. D. G. Brinton has 

 described, in a paper read before the Ameri- 

 can Philosophical Society, a specimen of 

 these foot-prints, sent to him by Dr. Earl 

 Flint, of Eivas, Nicaragua. The volcano of 



