RECENT DETERMINATIONS OF THE VISCOSITY OF WATER. 189 
seconds and 241-9 seconds, and these are the means of from two 
to four observations. 
Pagliani and Batelli 1885. —Pagliani and Batelli’s observations! 
were made at the temperatures 0:2, 0°5, 10-9 and 11:25 C, the 
effiux times ranging between 622-7 and 437-5 seconds. Their 
reduction give 1372 as the value of the fluidity at 10° C., that at 
0° being 1000, which happens to be identical with Slotte’s deter- 
mination, see table of results hereinafter. 
Traube 1886.—Traube’s efflux measurements? were made with 
two tubes, from two to four observations being taken at each 10° 
from 0° to 60° C., but his temperatures are apparently uncertain 
to 0-1 below 30° and 0°5 at the higher temperatures, these 
uncertainties producing however but insignificant errors in regard 
.to his purpose.2 His efflux times range between about 96 and 
366 seconds. As he used Hagenbach’s correction his results have 
been reduced afresh, and Boussinesq’s correction applied, %.e., 
m=1:12. The tabulated results are the means of his two measure- 
ments which differed in no case more than 0-7%. 
Noack 1886.—In the same year Noack* also made efflux obser- 
vations between the same limits, but at about 5° instead of every 
10°. The fluidity values hereinafter given. were obtained by 
increasing his kinetic energy correction by 41% as he had used 
Hagenbach’s factor. A complete and independent reduction could 
not be undertaken because the necessary data were lacking. In 
the reduction to every fifth degree, second differences were taken 
into account, and as the interpolations were never for more than 
1-6° 
\ 
this procedure was amply rigorous. 
Lo Eee eee 
~ 1 Sul’ =n interno nei liquidi—Atti d. R. -Accad. Torino, Vol. 20, 20, 
Pp. 607 - 885. 
5 Alga a innere Reibungsconstante und die —— Zihigkeit 
arpa lssigkeiten und ihrer wiisserigen Lisungen —— 
esell. Bd. 19, pp. 871 — 892, 1886. : 
3 See p. 875, 
‘‘ Ueber die Fluiditit der absoluten und verdiinnten pas caer 
ied. Ann. Bd. 28, pp. 666 — 684, 1886. 
