492 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ December 4,18D. 
prizes. Colonel Bird moved a vote of thanks to the Judges, President, 
and exhibitors. He thought that they should all bear in mind the fact 
that it was to the gardeners who had reared up the plants so tenderly 
that their thanks were in a great measure due. 
- Grape Growing and Grape Keeping.- In reference to 
Mr. Westcott’s remarks, page 446, I have concluded that he has never 
given the prescription referred to a fair trial, but has used it in a rough 
state, which accounts for his statement that such a compound could not 
possibly enter into the crannies where mealy bug and other insects 
generally lodge. Had the mixture been run through a fine sieve and 
properly painted on the Vines, and not have been merely smudged on, 
as Mr. Westcott is pleased to term it, his experience would have been 
quite different. At present I am having the vineries painted, but as I 
do not syringe the canes I have no fear of the houses being disfigured ; 
and supposing I did syringe, I would not go at it with all my strength, but 
would simply send a light spray with just sufficient force to reach the 
Vines, and in this case there would be no fear of the house getting 
bespattered. It is a mystery to me why Mr. Westcott wants to syringe 
with such force. My experience is that to syringe in this manner is 
very injurious. The method I have advocated for destroying insects on 
Vines is most economical and effective. I am well aware of the pro¬ 
perties of certain insecticides, but to saturate a cane thoroughly with 
any of them so as to destroy mealy bug, &c., will prove injurious, 
to clear all the bark off will also do harm, and to solely depend on 
sponging throughout the year is a long and tedious method, which 
generally fails, especially when there is a press of work. Experience 
has taught me how effective my practice of destroying insects is, and I 
mean to keep to it till one is proved to be better, which Mr. Westcott has 
failed to do.— S. Scott. 
IRON. 
Its Use in Connection with Fruit Culture and Diseases. 
Iron is present in igneous rocks, in volcanic as peroxide 5T7 per 
cent, plutonic as peroxide in Cornish grey granite 1 97, prot¬ 
oxide HOI, up to 15 76 peroxide in Swedish trap. These rocks 
weather down into very much the same kind of soil. The rocks 
are termed felstones, felspar ; greenstones, diorite, gabbro, 
diabase, dolerites, all having a greenish colour ; and greystones, 
felsites, trachytes, and lavas. Felspar is among the most important 
rock forming minerals, occurring abundantly in granites (Peter¬ 
head)—iron peroxide F49, iron protoxide 0 43, and the character¬ 
istics are the potash felspar and soda felspar, also lime felspar. In 
potash felspar the potash varies from 4 to 16 per cent., and the soda 
rises from nothing to 10 per cent. In soda felspar the soda rises 
to 12 per cent, lime taking the place of potash. In the lime felspar 
lime rises from 6 to 20 per cent., and soda from 1 to 8 per cent. 
The felspars occur in all traps—Swedish, as just stated containing 
iron peroxide 15'76. Greenstone or whinstone is a mixture of 
hornblende and felspar, and syenite has felspar for its most abun¬ 
dant ingredient—iron peroxide 2 57, iron protoxide 5 75 ; diorite— 
iron peroxide 9 27 ; greystones—felsite contains iron protoxide 
2 69 ; trachyte—iron peroxide 5 17 ; lavas—iron peroxide 5 69, iron 
protoxide 5T3. Iron, therefore, is abundant in the igneous rocks. 
They are naturally digested in carbonic acid water, which removes 
the alkali and disintegrates the mineral-producing clay—sedimen¬ 
tary or mechanically formed soils—viz., argillaceous or clayey, and 
arenaceous or sandy, which are termed aqueous rocks through 
deposition in water ; stratified, yet granular in texture. 
Besides the mechanically or sedimentary formed aqueous rocks 
just mentioned there are of the same order chemically, and 
organically formed rocks—viz,, calcareous, silicious, phosphatic, 
carbonaceous, and ferruginous. There are also metamorphic rocks, 
or those the original character of which has been altered by new 
chemical combinations ; limestone, for instance, converted into 
marble, sandstone into quartz, clay into slate, slate into schist, &c., 
approximating to the character of igneous rock, and in all we find 
iron, except in Carrara marble and Italian dolomite—viz , Welsh 
slates contain iron protoxide 7*83, and Cornish slates iron protoxide 
5T4, and iron peroxide 13 39 per cent. 
This matter may seem foreign to our subject, but it is of 
primary importance that we understand how rock originated, what 
it is composed of, and what kind of soil it will break down into 
when exposed to the atmosphere. Geologists tell us that four- 
fifths of the earth’s crust consist probably of felspar and quartz. 
Felspars are double silicates of alumina and potash, or soda, or 
lime ; quartz is oxide of silicon or silica, best seen pure in sea sand ; 
micas are silicates of alumina, potash, or magnesia, with oxide of 
iron ; hornblende contains silicates of magnesia, lime, and prot¬ 
oxide of iron, alumina being replaced by iron oxides and magnesia 
We have given enough to show that soil is due to the decay of 
igneous rocks, and as iron enters into their composition it follows 
iron must form an ingredient of most soils. Felspar, it has also 
been stated, is the most abundant of all minerals, that its decom¬ 
position is due to carbonic acid gas (carbonic dioxide) in water ; 
the lime, potash, or soda they contain is converted into a soluble 
carbonate, the silica set free remaining impalpable, which with the 
silicate of alumina forms an unctuous, plastic, yet mealy powder, 
chemically termed hydrated silicate of alumina, and geologically 
kaolin, its composition—silica 46 - 4, alumina 39*7, water 13*9 ; but 
the per-centages vary, and lime, magnesia, potash, soda, and iron- 
peroxide may or may not be present ; mineral silicates resulting of 
the disintegration of hornblende containing iron protoxide 18 - 75, 
therefore besides kaolin or clay igneous rocks furnish lime, 
magnesia, peroxide of iron through oxidation of protoxide, and a 
hydrated silicate of protoxide is a product of the alteration, hence 
the abundance of iron silicate in sedimentary strata, and it is the 
presence of iron that gives the colours green and brown to clays. 
White clays are derived from serpentine, and often contain 33 per 
cent, of magnesia. Red clays contain iron peroxide 6*84, protoxide 
0'32. They are of the coal measures and other strata, probably 
derived from similar rocks to basalt clays, which contain from 9T7 to 
14-87 protoxide. In the change from the rock to the soil there is 
a loss of lime one-fiftb, soda one-third, very little potash ; but 
great gain of alumina, and iron oxides one-fourth. Ultimately the 
greatest losses is in potash and soda, then lime and magnesia, next 
silica and iron. 
Iron is the basis of most rock pigments—they are red, brown, 
yellow, green, according to oxidation and hydration. Silicious 
cement forms sandstones, sand cemented by lime forms Kentish 
rag ; if felspars intersperse millstone grit results, or if clay and 
sand get together we have new red sandstone. Sand particles 
cemented by peroxide of iron form red, yellow, or brown ferru¬ 
ginous sandstone, the upper greensand are green through silicate of 
iron, and the pudding stones of Hertfordshire are held together by 
calcareous, argillaceous, silicious, or ferruginous cement. Brick- 
earth, also brown or reddish loam, enclose calcareous concre¬ 
tions ; gravel is an aggregation of rooky fragments embedded in 
finer material, cemented into solid rock it is conglomerate, and 
shingle is rounded rock fragments. Sandstones are not very 
irony, 0 25 is a minimum as in chalk flint ; red sandstone contains 
peroxide 1 *30 ; carboniferous a little in combination with alumina; 
also magnesian in similar combination. 
Alumina is the basis of all clays ; they are plastic combined 
with water, and harden when exposed to heat. If they are burnt 
water enters into no chemical combination when absorbed, but if 
charred, clays retain their chemical properties. Dark bluish-grey 
colour denotes oxide or sulphide of iron, often organic carbonaceous 
matter, and all clays emit an earthy smell when breathed upon. 
Clays are more or less calcareous ; cement stones arise in some, or 
clayey matter separated by lime, and clay ironstone occurs in segre¬ 
gated masses in rocks or shales. Finely divided and intimate 
mixture of clay and sand constitute brick-earth or clay mixed 
with fine sand, the latter in such proportion as to allow water to 
percolate the mass freely and prevent its cementing together, and 
is a good example of loam. The light brown colour of many loams 
is due to peroxide of iron. Blue clay contains iron protoxides, 
4T7 ; cretaceous, 6'7; white (carboniferous), 2'95 ; red (car¬ 
boniferous) iron peroxide, 6 - 84 ; protoxide, 0 32 ; marls contain 
iron along with alumina, chalk marl, 3 04; clay marl, 1H92 ; 
sandy marl, 3’8 ; while new red contains 25 38 per cent, of 
alumina and iron oxide. 
Limestones contain varied amounts of iron. Chalk with flints 
contain iron and alumina, 042 ; Portland limestone, 2 0 ; Kim- 
meridge, 8 2 ; oolite, H20 ; magnesian limestone, P8 ; Silurian 
limestone, nil ; red chalk (Norfolk), 6*4. Argillaceous (clay) lime¬ 
stones owe their bluish grey colour to bisulphide of iron, which 
exposed to the influences of air and rain, is oxidised into the sulphate 
(ferrous sulphate), and in the change effected by the sulphuric 
acid uniting with the alkaline bases (alumina, lime, magnesia, &c.), 
the protoxide becomes hydrated peroxide of iron. The dark colour 
of rich cultivated lands is due to their being furnished with 
abundance of organic matter. Minerals present having a basis of 
iron-protoxide impart a bright deep green colour to rocks. Decom¬ 
position sets in on exposure, silica is set free, the iron taking up 
water and additional oxygen converted into a hydrated peroxide, 
consequently the rock loses its green colour, passes to yellowish 
brown as seen in the soils of the upper and lower greensand. 
Argillaceous beds contain concretions of iron pyrites, become 
oxidised on exposure into sulphate, then pass into brown hydrated 
oxide. To that and the decomposition of another small portion of 
iron sulphide is due the change in the London, Kimmeridge, and 
Oxford clays from dark bluish grey at varying depths to a light 
burnt umber brown near the surface. 
