52 
REPORT— 1847 * 
to this class of ra 3 r 8 that the scorcliing influence is due, there is every reason to mb- 
elude that the use of this glass will be effective in protectiug the plants; andst tie 
same time as it is unobjectionable in point of colour, and transparent to that principle 
which is necessary for the development of those parts of the plant vliicli depend 15 ^ 
external chemical excitation, it is only partially so to the heat rays; and it« ufth 
10 fliooe only which are the most injurious. 
'Hie phiss is manufactured by Messrs. Chance of Birminghatn, and the ilwBct “ 
the oxide of manganese^ commonly employed in all sheet glass, is insisted 00 , tt 
haring been found that glass, into the cimipositimi of which manganese enters, »« 
after exposure for some lime to Intense sun-light, assume a pinky hue, and ur jinl 
of tin's cliaractcr would completely destroy the peculiar properties for which thaglm 
11 chn*en. 
Mellniii, in hi* investigationH on radiant heat, discovered that a peculiar gr«Dgl*s 
manufactured in Italy obstructed nearly all the calorific rays; we may therefnn^ 
elude that the glass chosen is of a similar character to that employed by the Italiu 
philosopher. 
The tint of colour is not very different from tliat of the old crown gUss, 
practical men state that they find their plants flourish much better under this bw® 
ginss thnii under the white sheet glass which is now so commonly employed. It® 
satisfactory thus to find practice confirming the conclusions of science. 
On the Electrolysis of Water. 
Ey the Rev. Dr. IIohinson (in a letter to W. R. Grove, Esq.)- 
The paper on this subject, by Dr. Robinson, has been printed in the Tran«J‘>«‘'' 
of the Royal Irish Academy. 
On the Quantity of Electrolysis as affected by the extent of the SectioiviiM^ 
of the Electrolyte, liy W. R. Grove, F.R.S. 
rhe experimenis here described were made two years ago, and were intendedu'^ 
commencement of a scries of researtlie* on the influence of quantity in 
meri , both as regarded the and also the cow</Mctiff^ portions of the c' 
single cell of a zinc and platina dinphrngin hatfery charged on the 
Jtth peroxide ofmanganwe and hydrochloric acid basamore intense 
rtccmniH^p more waur in a given time thau a similar battery charged with 
acid; hut two or more cells of the former, arranged in series, are far 
• 1 , number t)f the latter, particularly if large electrodes he employed. 
nority ui the chlorine battery arises, 1 believe, from want of quantity in 
.. , ^ oaiiery arises, 1 believe, from want ol quaniuy •» 
STi M the chlorine is slowly liberated and much diluted by 
J , nitric acid supplies an indefinite quanii^ of 
iOUlH UXVpcn* PhlL4 fHp lo in An 
electrolyte is smaller in the fi'm case than in the 
admitted ihat jn luetnlUc conductors the facility of conduction is " „j,x 
coiidncting substance; but the probk-m is rendered itiiw 
tiv >1, ° polarization or reaction occasiotied by the liberated 
w’l,..fi.^..*lk*"^*^ efficient chemical ingredients contained in the 
*^*1 dtteclly as ions or aocondnrily hj' absorbing or prerentm? * . ' 
‘ I*" cathode. Dr, Faradav. in bis ‘ Researches, h" ^ 
«f 0,1. electrode*, interposed in the same circuit, yield ‘I** **“®^*f*rd 
l>een misinterpreted 
tvib. *,..1 I - , .i--"'"'-'- application of voltaic electnciqriv‘“‘^^, 
1 ' ^clievi< I*wno1k has promoted, this error has now for 
V 8 the first to point out the necessity of electrodes equal at 
