225 
GARDENING AS A SCIENCE. 
No. X.— WATER. 
This most wonderful of fluids, which might, without mucli violence to the 
understanding, be considered the base of alt created things, was supposed to be a 
simple element — one of the four; and even now the associated terms, fire, water ^ 
earth, and air, are familiar, and come trippingly off the tongue. Little more than 
sixty years have elapsed since the theory of the early chemists was abandoned, 
after our countrymen, Priestley and Cavendish, had effected the decomposition of 
water; and the discovery had been detailed in the Memoires of the French 
Academy in 1781. 
A variety of experiments are described in books of modern chemistry ; but 
none are so conclusive, sublime, and illustrative, as those of Faraday, which are 
found in his Experimental Researches on Electricity/, the whole collected from the 
Philosophical Transactions of the Royal Society, in an octavo volume, published by 
Taylor, 1838. 
The decomposition of water by means of the galvanic, or voltaic battery, 
produces, in the purest state, two gases, which have been already alluded to, and 
always in definite proportions. Thus, as stated by Brande, with an accompanying 
diagram (Manual, p. 275) — "If a glass globe, with two orifices, each have a 
tube adapted to it, so as separately to receive the gas from each wire, it will be 
seen that ttvo volumes of liydrogen gas and one volume of oxygen gas are respect- 
ively collected in the tubes, the one inserted over the negative wire, and the other 
over the positive." 
But the hydrogen separates, always, at the negative pole, and therefore is a 
positive electric ; and though double the oxygen in volume, is only of its 
actual weight. Hydrogen gas, therefore, is separated into infinitely minute 
particles or atoms by electricity, so much so, that it is deemed to be the lightest of 
all material substances that have weight ! 
Now, it is clear that these gases, hydrogen and oxygen^ had existed together in 
the form of fluid water ; but that a stream of electricity being passed through the 
water effects a separation of the elements of that fluid, and produces them in the 
form of gas ; a condition in which the particles are in a state of extreme division. 
Of the phenomena of separation we are enabled to obtain some idea by referring to 
the following paragraphs of Dr. Faraday's Seventh Series, at p. 250. 
" It is wonderful to observe how small a quantity of a compound body is 
decomposed by a certain portion of electricity. Let us, for instance, consider this, 
and a few other points, in relation to water. One grain of water acidulated to 
facilitate conduction, will require an electric current to be continued for three 
VOL. IX. NO. CVI. G G 
