No. 6. DEPARTMENT OF AGRICULTURE. 779 



more than can be said for every new Carnation that is disseminated, 

 many varieties being absolute failures in some sections of the 

 country; whether it is the soil, the climate, or the water, which does 

 not suit them has not yet been determined. 



VENTILATION. 



One of the most important matters in connection with the success- 

 ful management of the greenhouse is the ventilation. It is very nee 

 essary, not only to keep the temperature within down to the mark, 

 but it is also necessary in order to make as complete a change of the 

 inner atmosphere as is possible. 



In the olden time when greenhouses w'ere frequently, we may say, 

 generally built with sashes made for the purpose, the mode of ven- 

 tilation was to slide them all down from the top, or as many of them 

 as were left loose for that purpose, or according to the weather, and 

 with the pipes for heating purposes arranged beneath the stages, 

 thus a thorough circulation was made and the air changed. 



Nowadays, however, few greenhouses are built with sashes, but in 

 stead, by what is known as a fixed roof, and arrangements are made 

 whereby sashes are hinged at the apex and lifted by a machine made 

 for the purpose, and by which the temperature may be regulated to 

 a nicety. 



There is an automatic ventilating apparatus on the market, which 

 works with complete accuracy. It is operated by water pressure, 

 but it cannot be operated satisfactorily unless there is guaranteed 

 water pressure under control of not les»s than twenty-five pounds. 

 This is a wonderful contrivance, and is a great labor-saving machine. 

 Its cost, however, may se^-m to some prohibitory. 



THE WATER SUrPLY. 



The water supply is one of the first and most important matters 

 to be considered in the starting of a greenhouse. 



Not more than twenty years ago, even within city limits, cisterns 

 were built inside the greenhouses in which to catch the rain-water 

 which fell upon the roof, and many old-time gardeners to-day prefer 

 the water secured in that waj^ to any other for the purpose indi- 

 cated, as they claim it is more soft and richer in the essential plant- 



