320 
of m arcs of oscillation, or the length of the mth arc of os- 
-cillation, or the reading of the mth turning point may be 
taken for the abscissas, but these methods require that the 
starting point in all determinations be absolutely the same, 
and that the index be adjusted exactly at the zero point of 
the scale. These precautions are not necessary if the ab- 
scissas are made to correspond to the logarithmic decrements. 
obtained with each solution, as these are not materially 
affected by slight changes in length of arc. Four place 
logarithms may be used and the logarithmic decrements. 
found taken as whole numbers, for the construction of the 
curve. See fig. 2, which represents a curve of this kind on 
a much reduced scale. 

PEER SEES PATS PRAT eep ey eye feu epee 
lethal TePal ebay le Toa irae by aie] 
UAE rs 0 ST a WE ee 
HE bh i 
|_| ADE dF Os Wk AD 
Grams of Sugar 
per liére 



S 
= fa 




pe i 
SRDARD Mrmr 
pd Dobe LT aT ee le ae 
EK Hp 
Bein Mee Se 
SRG M SE Dae 
ERR RO SERENA 
> 
SESSREREG 
|| 
a 
zB 
N 
E 
|_| 
aE 
Ss 
|_| 
|_| 
|_| 
a 
|_| 
| 
|| 
| 
LS 
| 
Ez 
|| 


ee Me 
NI 




Ra 
aoe 2 
AARRS 
SSEBS 
Sar Re 
RAS 
RlERES 
nm 
Sas 
[| 

Logarithmic Decrementes. 
Fig. 2. 
Having constructed a curve in one of these ways the vis- 
cosity of any liquid, more viscous than water, may be re- 
ferred directly to a solution of sugar of the same viscosity, 
in which the amount of sugar is known, and this expressed 
in grams per litre gives the viscosity, on the scale adopted. 
The utmost care is necessary in adjusting the tempera- 
ture of the liquid tested, as very slight changes have a 
marked influence on the viscosity, increasing it rapidly as 
i es 
