296 
Analyses of Boohs. 
[May, 
chical energy, and a bridge looms vaguely between, shall we say, 
matter and spirit ? Dr. Cleland accepts the latter suggestion, 
and, though with admitted diffidence, formulates the startling 
conclusion that “ a certain minute of energy in the production of 
sensation quits the physical for the psychical world, instantane- 
ously to return again in the excitation effected by the sentient 
mind on the substance of the brain.” But if thought and phy- 
sical energy are mutually convertible, is not thought, after all, a 
form of physical energy ? We can understand more or less 
clearly the mutual transformation of mechanical work, of heat, 
light, electricity, and magnetism ; but if we see such energy 
transformed into thought, and thought re-transformed into phy- 
sical energy, we are perplexed if the two are essentially distinct. 
To understand such a conversion is fully as difficult as to under- 
stand the identity of thought and cerebral change. 
Whilst, however, we do not for the present feel free to accept 
Dr. Cleland’s startling conclusion, we think that he has done 
well to raise a question which has hitherto been accidentally or 
purposely overlooked. The steps between an impression upon a 
sense-organ and the operations of mind and brain have not been 
closely tracked. 
We strongly recommend this pamphlet to the serious study of 
all who feel an interest in questions concerning the human mind e 
No special biological knowledge is required for its understanding, 
and it is full of important and suggestive matter at which we 
have merely taken a passing glance. 
Report on the Botanic Gardens , Trinidad , for 1880, laid before 
the Legislative Council October 1st, 1881. Port of Spain : 
Government Printing-Office. 
We have here a most interesting and many-sided report bearing 
on the climate, the flora and fauna, the resources and production, 
present and prospective, of the island. Meteorological observa- 
tions have been made of a regular and thoroughgoing character, 
so as to give a very fair picture of the climate. The annual and 
monthly rainfall, the atmospheric humidity, the cloudiness, the 
atmospheric pressure, and the temperature are very fully recorded. 
In the last point we notice the great regularity of an equatorial 
climate. For 1879 the mean temperature was 80*3° F. at 
9.30 a.m., and 80*9 at 3 p.m. The yearly mean temperature for 
the nineteen years from 1862 to 1880, as calculated from the 
mean maxima and mean minima, ranged from 76-0 for February 
to 79’4 in May, and 79-0 F. both in September and Ocftober. 
There are thus two maximum points, and the yearly average 
