POPULAR MISCELLANY. 



715 



cisms of experts, to be only a confession of 

 weakness rather than a disposition earnestly 

 to consider the whole question with a view to 

 the radical remedy of the evils. The human 

 nature of the judge is recognized and pro- 

 vided against. . . . The jury is selected so 

 as to be free from bias, and is protected as 

 well. Other witnesses are not expected to 

 take the part the scientific expert is almost 

 compelled to take. In fact, if deliberately 

 planned, there could hardly be a network of 

 conditions devised calculated to produce so 

 many of the evils of scientific expert testi- 

 mony complained of or to cloud this testi- 

 mony of highest intrinsic value, having the 

 highest degree of certainty, and in a field 

 altogether its own." These witnesses are 

 sometimes supposed to be selected on ac- 

 count of their ability to express a favorable 

 opinion, when they are flippantly styled 

 " adroit advocates of the theory of the party 

 calling them " ; but in how many cases, 

 Prof. Himes asks, " does favorable opinion 

 or bias, if you please precede the call of 

 an expert rather than depend upon the 

 call?" And the still more pertinent ques- 

 tion, " How many experts are not in the 

 particular case because their opinions are 

 not wanted by the party who consulted 

 them ? " 



Death Valley, California. The principal 

 features of popular interest in Death Valley, 

 California, as described in Prof. Harrington's 

 Notes on its Climate and Meteorology, are its 

 excessive heat and dryness. The tempera- 

 ture rises occasionally in the shade to 122, 

 rarely falls at any time in the hot months 

 below 70, and averages 94. It is not only 

 hot in the summer, but consistently hot, and 

 the heat is increased by occasional hot blasts 

 from the desert to the south. The air is not 

 stagnant, but in unusually active motion. 

 Gales of a few hours' duration are very com- 

 mon, and sometimes produce sand whirls 

 and sand storms. Rains may fall frequently 

 in the mountains and occasionally in the 

 valley. Clouds are by no means lacking, 

 and water can probably always be found in 

 the soil at the depth of a few feet, yet the 

 heat and wind together keep the surface 

 very dry and the relative humidity low. 

 Animal and plant forms are comparatively 

 few, and the former are usually nocturnal to 



avoid the heat. Both heat and aridity are 

 increased by the character of the valley. It 

 is' narrow and deep, apparently the bed of 

 an old sea, inclosed by high and dry moun- 

 tains. The white and shifting sands become 

 much heated under the noonday sun ; the 

 rest of the surface is in part salt and alkali, 

 in part probably wash from the mountains, 

 and in part a loose, spongy earth, over which 

 it is difficult to move. With the exception 

 of a few springs, the water is bitter and un- 

 wholesome. The meteorological features of 

 interest lie, for the most part, in those modi- 

 fications of diurnal changes which are due 

 to the topography. The range of tempera- 

 ture is unusually great. The hourly progress 

 of the wind shows enormous changes in 

 speed, in direction, and in temperature. The 

 diurnal change in the barometer is the most 

 characteristic of the form found in conti- 

 nental valleys. It is of the purest single 

 maximum type and has the largest ampli- 

 tude known. With these features go sharp 

 thunderstorms, limited to certain hours of 

 the day, and daily gales and hot blasts. It 

 is also noteworthy that the absolute humidity 

 here is fairly constant, and is that belonging 

 to that part of the world. The air in the 

 valley is part of the general aerial ocean, and 

 this shows no sharp contrasts in its moisture 

 contents, except when wind prevails across a 

 mountain ridge. Here the prevailing winds 

 are up and down the valley, and its relative 

 aridity is due to its higher temperature. 

 The winter climate is believed to be cool and 

 salubrious, with an inch or two of rain. 



The Vacuum Jacket and Liquid Oxygen. 



Prof. Dewar protects his liquefied gases, in 

 order to keep them in that state, from the 

 heat of convection, by inclosing them in a 

 vacuum jacket ; and from the heat of radi- 

 ation by silvering the surface of the contain- 

 ing vessel. He is thus able to keep liquid 

 air for thirty or forty hours. The vacuum 

 used contains a little mercury vapor, which, 

 though present in very minute quantities, can 

 be condensed into a bright mirror by cooling 

 the outside surface of the vessel with liquid 

 air. Among the experiments made in one of 

 Prof. Dewar's lectures to illustrate the prop- 

 erties of liquid oxygen, alcohol, which freezes 

 at 120, solidified when dropped into it, 

 and in that state would not take fire. So- 



