2094. The scorching of the leaves of plants under the large panes of glass. Mr. Hunt, as we have already sent, attributes this result to the transmission of the red or heat-giving rays, and thinks that if their progress could be impeded, the cause would be removed. Dr. Lindley, in the same very able article in the Gardeners' Chronicle from which we have already quoted, suggests that 'the scorching which has been complained of has arisen from a high temperature caused by imperfect ventilation. In the old crown-glass houses the panes were small, the laps large and numerous; and thus an abundance of apertures existed through which heated air could freely pass. In sheet-glass houses the panes are long, the laps few or none, and the means of escape for heated air reduced to a minimum. In many cases, no sufficient provision is made for the removal of the dry and scorching heated air. Hence arise unexpected accidents, which have been erroneously ascribed to the quality of the glass rather than to the imperfect construction of the houses.' (Gard. Chron. for 1848, p. 155.)
