464 HARSHBERGER— INFLUENCE OF SEA WATER [April 22, 



Density at 25° is 1.00774 for first and i. 01 751 for second. 

 For first, the change in density for 5° is 



1 .00898 — 1 .00774 = .00 1 24. 



For 3° it is f of .00 1 24 = .00740. 



Hence density is 1.00898 — .00740^1.00824 at 23°. 



For second change in density for 5° is 



1.01886 — 1.01751 = .00135, 



For 3° it is f of .00135^.00081. 



Hence density at 23° is equal to density at 20° — loss for 3° or 

 1.01805. 



We now have densities at 15° as i.oi and 1.02 as limits and from 

 observations we see that at 2^^° the density of our solution is 1.0155. 



We also have this proportion which will give a sufficiently 

 approximate result : 



H 3? is the density of this solution at 15° 



y — I.OI I -0155 — 1.00824 



1.02 — I.OI 1. 01 805 — 1.00824 



3' — I.OI .00726 



.01 .00981 ' 



3' = I -o I + .0074, 

 3'= 1. 01 74, 



therefore density at 15° = 1.0174. 



As the above computation is a rather long one and must be made 

 for each of the actual readings obtained by the hydrometer, it has 

 been thought advisable to give the entire set of original readings at 

 various temperature and the corrected specific gravity at 15° C. 

 Such a table may enable future workers in the same field to make 

 their corrections at once by omitting the long computation otherwise 

 necessary'. The numbers in the first column of the table refer to 

 the observations as recorded in the field note book and which have 

 been added as subnumbers to the specific gravities placed on the map 

 of Shark River and Bay which comprises Fig. 4 of the text. 



