342 THE EARL OF BERKELEY, MESSRS. E. G. J. HARTLEY AND C. V. BURTON: 
We would draw particular attention to the results noted in the long series of 
experiments with a weight concentration of 183'000 gr. to 100 of water. It would 
seem, judging from the numbers in column (ll) with apparatus Aa (i.e., when 
oscillating) and apparatus Ab (no oscillation), that the results are more consistent 
when the “jump ” is small. 
Coming now to the experiments with apparatus C, it will be noticed at once from 
the three experiments of May 28, June 6, and June 12, 1914, that the further the 
bottom of the dipping tube is from the water level (these experiments, unlike a 
similar set with sulphuric acid, were varied by keeping the water-level constant and 
altering the length of the dipping tube) the smaller log, pjp 1 becomes. In other 
words, the quantity of water taken away from the water vessel is a function of the 
vertical distance between the water and the tube. 
Obviously one way of explaining this is by supposing that some of the water which 
was originally in the air-stream condenses on the sides of the vessel before it reaches 
the dipping tube. That this explanation is probably correct is shown by the next three 
experiments ; in the first of these, the last branch of the water vessels was empty and 
consequently a large proportion of the water condensed in it; in the next two this 
branch was coated with either paraffin wax or “ bakelite, ” with the result that the 
normal values were regained. That these results are normal is shown by the two 
experiments with apparatus D, where the vessel is of quartz and the dipping tube is 
some 0'3 cm. away from the surface. 
Thus we have conclusively proved that no accurate results can be obtained with 
these glass vessels, unless the bottom of the exit tube is very close to the surface of the 
water; incidentally it may be remarked that such is actually the case with apparatus 
Aa and Ab. 
Air Pulses .—It will be seen that the deviations in log, p 0 /pi are larger than can be 
accounted for by the known probable error of weighing. During the search for an 
explanation of this, it was noticed that the results, when all other conditions were 
constant, seemed higher during the prevalence of gales. Unfortunately, this 
connection (if any) cannot be put on firm ground, because, as already stated, we have 
made as many alterations in the conditions as possible and consequently there are 
but few suitable experiments for comparison. 
Mr. J. W. Walker suggested that the anomalies might be due to the greater 
number and amplitude of the air pulses in high winds.* 
To reduce this source of trouble as much as possible the air current was altered so 
that there were no pulses of any kind either from the atmosphere or from the Fleuss 
pump, and the two experiments of June 24 and July 13, 1916, were carried out on the 
most dilute solution. The results show a satisfactory agreement and differ but little 
from previous experiments. One interesting fact requires mention. It was noticed 
* We were unable to test this hypothesis as the only suitable records of air pulses, those of Mr. Dines, 
are kept at the Meteorological Office and Sir N. Shaw would not let us have them for reference. 
