ADDRESS BY PROFESSOR TRAILL. xli 
dustry and Hospitals—of whom forty-one have already been accurately 
examined, for the object just aliuded to. 
The results of the Discussion of the Observations on the Tides, ob- 
tained by means of the grants of the Association, have been reported 
by Mr. Lubbock. 
_ Mr. Dessiou was employed to discuss the Tides observed at Liver- 
pool, so as to ascertain the diurnal inequalities in their height, and also 
to classify the errors of prediction for a year in Liverpool and at the 
London Docks. The result is, that Daussy’s deduction from the ob- 
servations at Brest is confirmed, viz. that the height of high water is 
diminished when the barometer is high, and increased when it is 
low. 
The varicus discussions of nineteen years of observations at the 
London Docks, amounting to 13,370, for the purpose of deducing the 
diurnal irregularities, and examining the effects of the moon’s transit 
immediately preceding high water, and those of the two previous days, 
lead to the conclusion, that Bernouilli’s theory of Equilibrium “ satis- 
fies the phenomena nearly, if not quite, within the limits of errors of 
the observations,” and that it leaves very little to be otherwise ac- 
counted for, 
A short statement is made by Professor Powell, of Oxford, on the 
Determination of Refractive Indices for the definite rays in the Solar 
Spectrum, from direct observation. The investigations recommended 
in the third Report of the Association have been commenced by Pro- 
fessor Powell, who continues his observations. 
Dr. Hodgkin reported from the London Physiological Commit- 
tee, that their investigations have not established the views of Lippi, 
respecting the communications of the absorbents with the veins; but 
they do not warrant a rejection of his observations, nor amount to any 
proof that the thoracic duct is the sole medium of communication be- 
tween the lacteals and the veins. Direct communications between 
absorbents and veins have been observed by the reporter: but he is 
disposed to consider these as deviations from the normal structure. 
A short Report on the best methods of ascertaining Subterranean 
Temperatures, and the proper form for Registers of such observations, 
is published by a Committee appointed for the purpose. 
The last Report in the volume is the very profound Examination, by 
Sir William Hamilton, of the Validity of Mr. Jerrard’s proposed me- 
thod of Transforming and Resolving the higher degrees of Equations, 
as contained in his ‘ Mathematical Researches.’ Mr. Jerrard’s method 
may be characterized as consisting in rendering the problem indeter- 
