4 MARKET NURSERY WORK 



there are certain fundamental principles in the management of 

 greenhouses that must not be overlooked. They are, in 

 character, hygienic. Whether the houses be heated or 

 unheated, the ideal must be to maintain an equable tempera- 

 ture, and the variations, as indicated by the thermometer,- 

 should be as little as possible. In the former, the heating 

 apparatus is the all-important factor ; in the latter, the 

 ventilating gear has to be relied upon. 



HEATING APPARATUS 



With the various types of boilers we are not here concerned 

 save to point out that, because of their vital importance, the 

 most efficient cannot be too good. There is no great difference 

 in principle between any of the standard makes, and their 

 efficiency and effective capacity is determined very much by 

 the degree of intelligence with which they are attended to. 



We have pointed out the need for maintaining an equable 

 temperature in the houses, and, apart from sun-heat, the only 

 other means of supplying warmth is the hot-water system. 

 Seeing how much is really at stake, how important it becomes 

 that the care of the boiler should be in careful, experienced, 

 intelligent hands ! The stoker should attend to his duties 

 regularly, systematically, methodically ; with his eye on the 

 thermometer. The flues should be carefully cleaned every 

 morning, the damper kept in smooth working order, and the 

 chimney free from soot. We have, in our experience, seen 

 disaster follow disaster when the stoking was left to boys or 

 to incompetent men who attend to their duties spasmodically, 

 sometimes making the hot- water pipes* too hot to lay the hand 

 upon, and at others allowing them to be dead cold. Stoking 

 ought to be learnt ; it is no job for the novice. 



VENTILATION 



In glasshouse construction the provision of the means of 

 ventilation should be scientific and practical. Not only must 

 there be top ventilation, but bottom ventilation is equally 



