168 



MR J. Y. BUCHANAN ON THE 



Scheme for Logging Observations — continued. 



Line. Symbol. 



.^10 



/n 



(J 

 h 

 i 



J 

 k 

 1 



m 

 n 







P 

 1 



dr 



dw 



w 



R 



I' 



T 



dr 

 dw 



dt 



dw 



a -s 

 C 







W„,o 



Explanation. 



Added weight w.'k, in grams : — Scale reading Rjo in millimetres. 



Mean increment of immersion produced by the addition of O'l gram to the external load. 



Mean added weight. 



Mean scale reading. 



Final temperature of liquid. 



Time when experiment was finished. 



Mean of initial and final temperatures. 



Difference of mean reading K from 50 mm. (50 -R). 



Weight which immerses dr millimetres of stem in the liquid. 



ib + chor : Added weight which produces immersion up to 50 mm. at T° C. 



= T - T : Departure of mean temperature from the standard temperature. 



Weight to be added to compensate the displacing value of dt. 



= w + dWi- + dwi : Total mean added weight required to immerse the closed hydrometer in the liquid up to 



50 mm. at the standard temperature, T. 

 Weight of air contained in the open hydrometer, less that of the air displaced by the exposed part of the stem. 

 = W+''i3;': — Total weight of liquid displaced by closed hydrometer when immersed in it up to 50 mm. at 



standard temperature, T. 

 = W + Avt + a : Total weight of liquid displaced by open hydrometer when immersed in it up to 50 mm. at 



standard temperature, T. 

 Total weight of distilled water displaced by hydrometer when immersed in it up to 50 mm. at standard 



temperature, T. 



"W + rwt 



for closed ' 

 hydrometer. | 



W + ,M( + a for open 

 W^;^ hydrometer. 



Specific gravity of the liquid at the standard temperature, T, referred to that of 

 distilled water at the same temperature as unity. 



Numerical Examples in the Case of 



(a) Distilled Water at 19'5" C. 



(b) 7'0 gram-molecule Solution of Rubidium Chloride. 





(«) 



w 





{a) 



(6) 



a 



Hydrometer A. 



Hydrometer A. 



9 



10-69 mm. 



7 '33 mm. 



h 



136-11132 grams. 



184-67847 grams. 



h 



0'77 gram. 



14^75 grams. 



c 



February 10th, 1910. 



July 3rd, 1911. 



I 



51-39 mm. 



51^65 mm. 



d 



10.15 a.m. 



11.15 a.ra. 



7 



19-50°C. 



19-50° C. 



e 



19-50°C. 



19-50° C. 



k 



10.26 a.m. 



11.32 a.m. 



u 



'37 grams. 8-5 mm. 



14-15 grams. 7-5 mm. 



I 



19-50° C. 



19-50° C. 



U 



0-47 ,, 19-0 „ 



•25 ,, 14-2 ,, 



m 



1-39 mm. 



1 '65 mm. 



U 



0-57 ,, 30-0 ,, 



•35 ,, 212 ,, 



n 



0-0130 gram. 



02251 gram. 



U 



0-67 „ 40-5 ,. 



•45 „ 29^0 „ 







0^7570 ,, 



14-72749 grams. 



U 



0-77 „ 51-5 ,, 



•55 ., 36^7 „ 



V 



none 



none 



u 



0-87 ,, 62-5 „ 



•65 ,, 44-1 ,, 



9 



none 



none 



fn 



0-97 ,, 73-0 ,, 



•75 ,, 52^2 ,, 



r 



0^7570 gram. 



14-72749 grams. 



h 



1-07 ,, 83-5 ,, 



•85 ,, 59^3 ,, 



s 



0-13508 ,, 



0-13028 ,, 



ft 



1-17 „ 94-0 „ 



•95 ,, 66-8 „ 



t 



.1. 





f^o 





15-05 ,, 74-4 ,, 



u 



... 



199-53624 grams. 



fv 





-15 ,, 81-5 ,, 



V 



137-00340 grams. 



137-00340 ,, 



fu 



... 



■25 ,, 89-1 ,, 



w 



... 



1-456433 



As 



... 



-35 „ 95-5 ,, 









The weight 137 '0034 grams entered in line v includes that of the air contained in 

 the hydrometer. Its value is obtained in the following manner : — 



As the result of many determinations, of which the example in § 84 is an 

 instance, the mean added weight necessary to immerse the hydrometer to 50 mm. at 

 19*50° C. was found to be 075471 gram. 



Hence weight of hydrometer and added weight = 136'86603 grams. 



Density of distilled water at 19-50° C. - 0-99834. 



1 r T -11 1 Til 136*86603 



Ihereiore volume oi distilled water displaced = o-QQft^A 



= 137*093 c.c. 



