1884.1 
Analyses of Books. 
611 
The author refers to two recent series of observations in hy- 
draulics, — the one a series of velocity observations made for the 
Government of India on the Ganges Canal. These observations 
“ clearly disprove the accuracy of the old hydraulic formulae for 
flow under gravity, and corroborate the positions laid down by 
the author in his first edition. The other set of observations 
referred to were condudted by Mr. Baldwin Latham on the tidal 
portions of the Thames, at the instance of the Corporation of 
London. The results of these^observations, however, have not 
yet been made public. 
Mr. Jackson finds it necessary to point out expressly that his 
tables for canals and culverts are not intended to apply to rivers 
of any sort, more especially the tidal. 
The second edition before us has been carefully revised, and 
certain errors, both of calculation and of topography, have been 
eliminated. Additional tables have been added to the extent of 
forty pages. 
That the work will prove direcftly beneficial to the engineering 
profession, and indirectly to all interested in drainage and the 
supply of water, as well as in internal navigation, is self- 
evident. 
H ay -Fever ; its Etiology and Treatment. A Ledture delivered 
at the London Hospital Medical College. (Reprinted from 
the “ British Medical Journal.” By Morell Mackenzie, 
M.D. London: J. and A. Churchill. 
Hay-fever is a fashionable disease of the day, and, although we 
never came across any person affedted by it, it would be idle, as 
do some, to doubt its existence. Dr. Mackenzie considers that 
the disease has of late years increased in frequency, and thinks 
it probable that irritating properties have been newly acquired by 
certain vegetable bodies. Such a change is by no means out of 
the question. But it cannot be overlooked that the disease is 
most common in two countries differing widely in climate and in 
flora, but both inhabited by a race given to over-work and mental 
tension under pressure. The two countries are, of course, 
England and the United States. The late Dr. G. M. Beard 
ranked hay-fever among the neuroses, though the pollen of 
grasses, &c., may be one of the principal exciting causes, — per- 
haps the principal. Dr. Mackenzie admits that out of millions 
of people, exposed alike to inhale the pollen of flowers, very few 
suffer. The liability appears suddenly, but when once acquired it is 
seldom lost, and the predisposition seems to increase with each 
succeeding season. The author states that it is rare on the Con- 
tinent of Europe. In Asia and Africa it attacks only the English. 
