242 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN’S COMPANION, January 6, 1857, 
regulations a few years afterwards gave an impetus to 
the calling, which the gardening community cannot be 
too grateful to the minister of that day for bestowing. 
| The increased demand for glass, however, at the moment 
! prevented its being furnished in sufficient quantities 
to meet the wants of the time, and therefore it 
retained a higher price than it ought, the consequence 
' of which was the introduction of large quantities of 
1 foreign sheet glass of an inferior kind into the market, 
to meet which the home manufacturer was obliged to 
furnish an article proportionately cheap, which had the 
bad effect of disseminating an improper glass, against 
■ which an outcry was made both far and wide, giving 
! rise to another kind of glass, rough plate, being called 
! into use. In the meantime, the advocates of sheet glass, 
who were willing to pay a fair price for a good article, 
| were at length supplied with one against which few 
j faults could be found. I might also add, that thickness 
as well as quality was increased at the same time, and 
1 believe few of those who were willing to pay the few 
| shillings more required for the good article had occasion 
j to regret their choice. 
About the same time that sheet glass became cheap 
and plentiful, coloured glass was recommended by some, 
and glass tinted with blue, green, and straw colour was 
more or less tried; but none of these colours met with 
much favour. Still I think the use of coloured glass 
was too hastily abandoned, for a greenhouse I once had 
to manage seemed to act very well that was glazed with 
sheet glass tinted green. This house was an excellent 
summer one, and 1 did not feel any inconvenience from 
it in winter. Observe, it had not a deep tint of green, 
but sufficient to stop the strong glare of summer sun¬ 
shine, and it being a span-roofed house, the lights on 
the north side were of ordinary clear glass, which 
answered the twofold purpose of admitting light where 
it could do no harm, and prevented plants becoming one¬ 
sided. One thing, however, must be said, that plants 
accustomed to a house of this kind did not like to be 
removed to one of another kind; and as there are but 
few of that kind in existence now, it is needless saying 
more about them. 
Now, as coloured glass has gone out of fashion, and 
but little of the old crown glass- is used in garden 
structures, except in repairing old houses glazed with 
that sort, the majority, if not the whole, of new ones 
erected of late years have been glazed with sheet or plate 
glass of some kind or other, the latter affording a great 
variety of the kind known as rough plate; and, as 
polished plate can hardly be expected to be within the 
reach of the million, it is only used in particular cases. 
The glass at present in most request is rough plate 
aud sheet, and on the respective merits of each a few 
words may be of service to those intending to build. 
At the same time I must admit that I have not had 
sufficient personal experience in rough plate to speak 
decisively on its qualities; that the opinion I give is 
more from what I have witnessed elsewhere, backed by 
the opinions of others on whom I can rely. Of sheet i 
glass I have had both good and bad to deal with; there- | 
fore I speak with more confidence on that. 
Sheet Glass : its Merits. —The good properties of 
really good sheet glass are various, while it is not with¬ 
out its defects; the foreign kind especially is so indif¬ 
ferent, that I may here caution the inexperienced who 
may be on the point of building a hothouse to stipulate 
for good British sheet to be used, i.e., if he prefers that 
kind, as much injury has been caused by substituting 
a. low-priced Belgian article for it, and I believe most of 
the evils complained of in sheet glass arise from the bad 
quality of the kind used ; but, as we are speaking of the 
merits of what is good, I class them thus :— 
1st. Appearance. 
2nd. Transparency, adapted to forcing-houses. 
3rd. Quality of keeping itself clean under ordinary 
circumstances. 
4th. Retaining the same appearance for years. 
5th. Is easy to cut, and thereby a favourite with the 
glazier. 
The above remarks are applicable to the good article, 
which certainly excels other kinds in the points enu¬ 
merated. We now come to the inferior kinds, which 
have several bad qualities, as under. 
Sheet Glass: its Demerits. —The evils complaimd 
of in this kind often arise from the bad kind used, aid 
are something like these :— 
1st. A wavy, uneven surface, forming a great number ! 
of imperfect lenses, which, acting on the plants, scorcn or 
burn them into unsightly specks. 
2nd. A more than ordinary brittleness, whereby squares 
are broken more often than they ought to be. 
3rd. Not so transparent as the better sort, aid, on 
being examined, presents a number of specks on one or 
both sides. 
4th. Changes colour tvith age, turning to a dark or 
rather dull purple tint after being acted on by a hot 
summer’s sun. 
Other points might be added to the above, but 
sufficient is given to show what is meant; but it is 
impossible to describe on paper the difference between 
good and medium glass; an inspection, however, will 
i do much that way, especially when there is a chance to 
see both good aud bad at the same time in use. For 
plant-houses, especially for those having plants in flower, 
shading will be necessary, even with good glass; but in 
forcing-houses well ventilated it ought to be dispensed 
with, and generally answers well. 
Bough Plate Glass: its Merits. —These are neither 
few nor unimportant, and it is not unlikely but it may bo 
improved. In the present case the remarks are confined 
to Hartley’s rough plate and the ordinary rough plate 
of other manufacturers; its merits may be classed 
somewhat thus:— 
1st. Strength to resist hail storms, &c., when large 
squares are used. 
2nd. Semi-transparency, thereby rendering shading 
less necessary for plant-houses than when sheet glass 
is used. 
3rd. A rough or partially fluted surface, which, instead 
of collecting the sun’s rays into a point, disseminato 
them in various directions; this, however, does not 
prevent the house getting heated. 
4th. Flatness, so as to fit the groove in the bar in all 
places. This flatness is not supposed to mean smooth¬ 
ness of surface, which is rough, as stated above ; but it 
is not bent up in a corner, as some other kinds of 
glass are. 
These remarks apply to the better description of 
rough plate in use; but this does not differ so much as 
sheet in its effects on plants, and the advocates for it 
are both numerous aud influential. 
Bough Plate : its Demerits. — These may be 
arranged somewhat thus :— 
1st. Indifferent appearance. 
2nd. Difficulty to cut, rendering it no easy matter for 
the glazier to fit in a broken square, which, in spite of 
all care, will now and then happen. 
3rd. Liability to get dirty after a lapse of years, the 
surface being rougher than good sheet. 
4th. Its non-transparency, rendering it objectionable 
for forcing-ho uses, where all the light possible is wanted, 
while it is scarcely sufficiently opaque to preserve plants 
in flower in summer without shading; or, as a labourer 
would say, “it is neither one thing nor the other.” 
Other points might be added to the above, but 
sufficient has been said to show that no kind is faultless, 
aud rough plate has as many faults as any other sort. Its 
appearance, certainly, is not good; and should the glazier, 
