GLASS AND GLAZING, PAINTING, ETC. 75 
thus have a very unfavourable effect upon the plants 
growing beneath. The foreign glass is also, from its 
hardness, more or less difficult to cut, and very liable 
to “fly,” while good English glass is nearly white in 
colour, cuts ‘‘soft”? to the diamond, and yet is tough 
and does not readily crack or fly. Some makes or 
‘‘brands” of the Belgian glass are considerably superior 
to others, but none are equal to good English material 
in softness, toughness, and transparency. Clear glass 
naturally admits more light than inferior qualities, and 
in winter practically every ray is of importance to the 
growth of plants. Glass full of ‘‘shakes’” and ‘‘ feathers ” 
should be avoided, as it draws or distorts the light 
sadly—indeed, it has been affirmed that such glass is 
one cause of the troublesome tomato disease known 
as the ‘‘droops” or ‘‘ falls.” 
Good Belgian glass (21oz.) can now be purchased, already 
cut to size, for about 10s. per 100 square feet, and if 
a large quantity is required at an even lower rate, while 
English glass of sufficiently fine quality for horticultural 
purposes costs very little more. 
What is known as 2loz. glass only ought to be used 
in the construction of glass-houses of any kind, the 
15oz. being poor thin stuff, unable to resist hail or even 
high winds, and constantly cracking and failing. In 
small squares it may be employed for cheap frames, 
small pits, etc.; but even then it should be carefully 
selected. , 
Except for such small frame-lights, etc., the very 
small squares of glass, often only 6in. by 4in. or less, 
that were so largely employed many years ago, are 
