Woeikof — CrolVs Hypotheses of Geological Climates. 169 



There is certainly a mistake somewhere ; or, rather the whole 

 method is a failure. How can we judge of the change of tem- 

 perature resulting from this or that distance from the sun, even 

 if we knew accurately the temperature of space,* when we do 

 not know the diathermancy of the atmosphere under different 

 conditions? We know only that it is exceedingly different, 

 according to the different quantities of carbonic acid and aque- 

 ous vapor contained in it, and in a far higher degree, according 

 to the absence or presence in different quantities of suspended 

 liquid and solid particles (clouds, dust, smoke, etc.) . Thus, 

 when we do not know in how far the loss of heat is impeded, 

 even an accurate knowledge of the temperature of space would 

 be of small use in this matter. I will illustrate this by a homely 

 example. Take a room where the fire is extinguished and the 

 hearth or stove cold in the evening, and try to guess at the 

 temperature the room will have in the morning. If we fol- 

 lowed the method of Dr. Croll, we should inquire only about 

 the outside temperature, and not about the thickness of the 

 walls, the windows, etc. I think that, taking the average con- 

 struction of Russian, English and Italian houses, if the inside 

 temperature was in all three cases 60° in the evening, and the 

 outside temperature —20 in Russia, 32° in England and 45° in 

 Italy, the morning temperature in the room would not be very 

 different, and probably even higher in the Russian room, owing 

 to its thick walls, double windows, etc. It is also interesting 

 to note, that a calculation, by the method of Dr. Croll, of the 

 mean January temperature of 60° N., as stated above, gives 

 lower figures than the extreme minima anywhere observed by 

 reliable thermometers; this latter is* about —81*4 F. (—63° 0.) 

 Neither in the coldest parts of northeastern Siberia, nor in the 

 highest latitudes of Greenland and Grrinnell Land, have lower 

 temperatures been noted, and yet in Flacberg Beach the sun is 

 absent from the horizon more than four months. The lower we 

 make the temperature of space, the more conspicuous is the 

 tenacity with which the surface of the earth and the lower stra- 

 tum of air retain a relatively high. temperature. 



Dr. Croll says in ' Climate and Time,' p. 43 : "The stoppage 

 of all currents would raise the temperature of the equator 55°, 

 that is, give it a mean temperature of 135°." Now such a 

 temperature is not only above anything known on the globe as 

 the mean temperature even of a single month, but the absolute 

 maximum known by exact observations does not exceed 131° 

 F. (55° C.) Though Dr. Croll repeatedly and quite rightly 

 points out the far greater influence of ocean currents over air 

 currents in modifying the temperature of the globe, he, quite 



* I just see that Prof. Langley claims to have determined the temperature of 

 space, but the actual figures and all details are still wanting. 



