Febeuaey 21, 1896.] 



SCIENCE. 



271 



extension of figure and structure; of some- 

 thing which has not motion or a combina- 

 tion of motions as force ; of something 

 which has not duration as persistence or 

 duration with persistence and change. 



In the mental world we have no knowl- 

 edge of something which is not a judgment 

 of consciousness and inference; of a judg- 

 ment which is not a judgment of a body 

 with number, extension, motion and dura- 

 tion. Every notion of somethipg in the 

 material world devoid of one or more of the 

 constituents of matter is an illusion ; every 

 notion of something in the spiritual world 

 devoid of the factors of matter and judg- 

 ment is an illusion. These are the propo- 

 sitions to be explained and demonstrated. 



In the following chapters an attempt will 

 be made to show that we know much about 

 matter, and although we do not know all, 

 all we know is about matter in its cate- 

 gories of number, extension, motion, dura- 

 tion and judgment, or that we know of 

 matter in its four categories and that we 

 know of mind in the categories of judgment, 

 but always this mind is associated with mat- 

 ter. In doing this we shall endeavor to dis- 

 criminate between the certitudes and illu- 

 sions current in human opinion. 



In the intoxication of illusion facts seem 

 cold and colorless, and the wrapt dreamer 

 imagines that he dwells in a realm above 

 science — in a world which as he thinks ab- 

 sorbs truth as the ocean the shower, and 

 transforms it into a flood of philosophy. 

 Feverish dreams are supposed to be 

 glimpses of the unknown and unknowable, 

 and the highest and dearest aspiration is 

 to be absorbed in this sea of speculation. 

 Nothing is worthy of contemplation but the 

 mysterious. Yet the simple and the true 

 remain . The history of science is the history 

 of the discovery of the simple and the true; 

 in its progress illusions are dispelled and 

 certitudes remain. J. W. Powell. 



Washington, D. C. 



NOTES ON THE DENSITY AND TEMPERATURE 

 OF THE WATERS OF THE GULF OF 

 MEXICO AND GULF STREA3I.* 

 I It is estimated that the evaporation in 

 the Gulf of Mexico amounts to about 60 

 inches a year, thus diminishing the amount 

 of water in the Gulf 1.54 cubic miles per 

 day. The evaporation is greatest in the 

 central parts of the Gulf, following a line 

 from east to west and approximately coin- 

 ciding with the line of mean maximum of 

 atmospheric pressure. 



Precipitation, on the other hand, is great- 

 est in the southwestern and northeastern 

 parts of the Gulf, and least in the area in- 

 tervening between the sandy plains of 

 Yucatan and the arid regions of southern 

 Texas and northern Mexico. By computa- 

 tion we find it to reach 32.7 inches annually, 

 which is about 55 per centum of the eva- 

 poration, and it increases the waters of the 

 Gulf by 0.84 cubic miles per day. 



The water supply is further increased by 

 river discharges, which amount to about 

 0.68 cubic miles per day ; nearly 70 per 

 centum of this volume being furnished by 

 the Mississippi River. It will be seen that 

 precipitation and river discharges feed the 

 gulf by nearly the same amounts, but the 

 effect produced by those feeders sinks into 

 insignificance when compared with that 

 produced by the inflowing current of the 

 Yucatan Channel, which, according to a 

 calculation from Lieut. Pillsbury's current 

 observations, hurls the enormous quantity 

 of 652 cubic miles of water per day into the 

 Gulf, which quantity by itself would suflSce 

 to raise the level of the entire Gulf 5f feet 

 within that space of time. 



The Gulf stream carries off only about 

 two-thirds of the water that is added to 

 the volume of the Gulf in the manner indi- 

 cated above, and evaporation being power- 



* Abstract of a paper read to the Philosophical So- 

 ciety of Washington, by permission of the Superin- 

 tendent of the U. S. Coast and Geodetic Survey. 



