INDEX. 559 



Paoe. 

 Water at greatest density, temperature of I95 2OI 



Water barometer devised by Mariotte, von Guericke, Daniell, and 



others 



422 



"Water, deep, slow change in the temperature of igg 



Water-pipes and gas-pipes good conductors of lightning 375 



Water-spouts resulting from tubular rarefaction of whirling air 361 



Water, the cohesion of, equal to that of ice 96 



Wave motion in electrical discharge 34O 



Weather indications, application of telegraph to 438 440 



Weather indications, the advantages of 455 



Weather-map at the Smithsonian Institution daily plotted by tele- 

 graphic despatches 290, 439, 440 



Weight of the atmosphere sometimes increased, sometimes dimin- 

 ished by added vapor 270 



Weight of vapor, method of determining 222, 223 



Weight of vapor, table of, at diiFerent temperatures 225 



Wells, Dr. W. C, investigations by, of dew and frost 248 



Welsh, Mr., observation by, on vapor-tension at elevations in bal- 

 loon ascents 268 



Wetherill, Prof. C. M., experiments by, on specific gravity of oils 



at different temperatures 492, 493 



Wind-belts shifted by change of sun's declination 82 



Wind, effect of, on different rain-gauges 261 



Winds, direction of the upper, indicated by the diffusion of volca- 

 nic smoke 281 



Winds of North America, character of 76 



Winds of the globe illustrated 276 



Winds of the United States, effect of, in distributing rainfall 287 



Winds the principal cause of ocean currents 60, 61 



Wilson, Mr., experiments by, on pointed electrical conductors 392, 393 



Wise, Mr. John, observations by, on upper winds in balloon ascents 281 

 Wise, Mr. John, observations by, in balloon ascents of an "hour- 

 glass " form of cloud 361 



Wise, Mr., observations by, of a discharge between parts of a cloud 393 



Wise, Mr., observations by, on upward currents in balloon ascents 297 



Young, Dr. Thomas, explanation by, of polarization of light 



through transverse vibrations 10-^ 



Zig-zag lightning the result of irregular conductivity 



365 



