April 13, 1883.] 



SCIENCE. 



271 



river nearly six hundred feet in height. This 

 •would form slackwater in the Ohio all the waj' 

 up to Pittsburg, submerging the site of that 

 city to the depth of two hundred and fift}^ or 

 three hundred feet, and setting the water back 

 far into the valleys of the Alleghany and Mo- 

 nongahela Rivers. 



In the extensive gravel-deposits of Ohio, 

 south of the glacial line, no paleolithic imple- 

 ments have as j-et been found ; but they may 

 be coniidently looked for. When they are 

 found, the investigations of Professor Wright 

 and his associates will have important bearings 

 in determining their age ; for, in man}' respects, 

 Ohio affords unrivalled opportunities for deter- 

 mining the amount of erosion which has taken 

 place since the ice of the glacial period with- 

 drew. So far, the evidence points to a later 

 date for the glacial period than that which is 

 advocated by some. The erosion which has 

 taken place since the glacial period is surpris- 

 ingly small. The streams running over the 

 glaciated surface occupj' very shallow vallej's. 

 In those rivers whose course was changed by 

 glacial action so as to produce waterfalls the 

 gorges are never more than a few miles long. 

 The period cannot have been extremely long, 

 or these streams would have done more work. 



THE WEATHER IN FEBRUARY, 1883. 



Destructive floods on the Ohio and tribu- 

 tarj- waters occurred from Cincinnati and 

 Louisville southward. The water rose higher 

 than ever previousl}- recorded, and propertj' 

 was destroyed estimated as worth $30,000,000. 

 Warnings were issued hy the signal-office ten 

 to fifteen daj-s in advance ; and merchants had 

 ample time, in most instances, to save their 

 property. The following table exhibits some 

 of the principal facts : — 



of homes, to imperilled health and comfort, 

 and to business delayed, cannot be estimated, 

 but are known to have been very extensive. 

 A very full report is given in the Monthlj' 

 weather-review of the signal-service. 



The month has been colder than the mean 

 for the region west of the Mississippi River. 

 The mean temperature was from 8° to 16° 

 below the normal on the Rocky-mountain pla- 

 teau ; it was slightly below the normal in the 

 north, east of the Mississippi ; and above the 

 normal in the south. In the whole country 

 east of the Rock}- Mountains the temperature 

 was 0.5° below the normal. The lowest tem- 

 perature reported was —57°, at Fort Washakie, 

 Wyoming. The rainfall of the Pacific during 

 the winter has not been sufficient to assure a 

 medium wheat-crop in that region. The defi- 

 ciencj' was over 4 inches in central California 

 and Oregon in February, and there were larger 

 deficiencies during the previous winter months. 

 This important crop, therefore, depends largely 

 upon the spring rains, which in this region are 

 usuallj- very light. On the other hand, there 

 has been a large excess of rain in the lower 

 lake-region and Ohio valley, the excess in the 

 latter region being 3.86 inches. 



Ice dangerous to navigation is slowly drift- 

 ing south to latitude 43°, between longitudes 

 45° and 48° W. 



The chart on the next page shows the mean 

 distribution of air-pressure and temperature, 

 with the prevailing wind-directions in the 

 United States and Canada. This chart shows 

 very high pressure over nearh' the whole coun- 

 try, it being from .1 to .2 of an inch above the 

 mean, except in Florida and southern Cali- 

 fornia. The areas of low pressure traced to 

 the Atlantic have all passed over the St. Law- 

 rence valley, and in no case has the centre of 

 any depression passed to the south of the Ohio 

 valley or middle states. 



The total number of storms that have been 

 traced in the United States during each Feb- 

 ruaiy since 1877 is given below. The mean 

 velocity of the storms, as pubKshed in the 

 . annual reports of the chief signal-officer, are 

 added for comparison. 



The last coliunn contains losses onl^- so far 

 as reported. The injuries due to sweeping away 



