38 THE FLORIST AND 
decidedly superior, and the lighter the materials composing the structure, 
the better. Heavy rafters and huge cornices must not be admitted, and 
nothing of an opaque character used, further than to secure sufficient 
strength. The majority of plant-houses are faulty in this respect, the 
material with which they are constructed being unnecessary, heavy and 
cumbrous, at once adding to the cost and diminishing the usefulness of the 
building. 
Many green- houses are rendered almost useless from the bad quality of 
the glass used in their construction ; the waviness and inequalities of infe- 
rior glass are sufficient to counteract the best efforts. An injurious amount 
of shading must be resorted to, to prevent foliage from blisters and 
blotches. These blisters are frequently attributed to sudden sunshines while 
leaves are wet. I have never observed anything of the sort occur under 
good glass ; neither do I consider it likely that it ever proceeds from that 
cause, whether the glass is good or bad. 
The investigations of chemists have done much of late years towards sim- 
plifying cultivation. A diffused knowledge of the elements of growth and 
their mode of action have also done much in improving ornamental plant 
culture. Twenty years ago, receipts for growing plants were as numerous 
as the plants themselves. Yague ideas were held in regard to the relation 
between soil and the vegetable productions grown upon it, and mysterious 
virtues were ascribed to certain mixtures of soils and manures. The intel- 
ligent floriculturist of the present day considers all such complicated com- 
binations as being altogether behind the age. He looks upon soil merely 
as affording support to the plant, as a medium for conveying nourishment, 
and where the roots have presented to them the various gases from which 
they derive their principal nourishment. Viewing it in this light, he is 
careful that the soil employed is of a character to offer no resistance to the 
presence of these gases. He finds no necessity for the services of a chemist 
to analyze the soil and ascertain its distinguishing properties, and has no 
anxiety to become acquainted with its chemical constituents. He can ana- 
lyze it sufficiently for his purpose at a glance, and see where and how it is 
defective, and supply its wants accordingly. His scientific knowledge 
teaches him that plants derive most of their food from air and water, 
and his practical knowledge convinces him that few soils are deficient in 
mineral ingredients, and however important the presence of certain specific 
mineral matters may be for the development of certain products, he knows 
that no combination of inorganic matter renders a due observance to its 
