A GENERAL SURVEY 7 



The attempt to grow the orange in these 

 northern climates presented a different prob- 

 lem because the trees had to be protected 

 during the winter. This resulted in the build- 

 ing of framework structures which were 

 covered during the winter with wooden shut- 

 ters and heated by means of a stone fireplace. 

 There was little or no glass used, but the 

 shutters were removed during the summer, 

 leaving nothing but the framework to ob- 

 struct the light and heat of the sun. A house 

 of this description, built early in the I7th 

 century by one Solomon de Gaus at Heidel- 

 berg, Germany, is said to have been 32 feet 

 wide and some 400 feet long, and to have 

 sheltered 400 orange trees. 



The next decisive step in the evolution of 

 the modern greenhouse seems to have been a 

 combination of the two preceding types, de- 

 signed for, the growing of plants during the 

 winter. They were permanent buildings 

 having opaque roofs and high side walls, 

 resembling dwelling houses, except that they 

 were well supplied with side windows. 



At this time it was thought necessary to 

 have opaque roofs to prevent freezing, and it 

 became common to have a second story, 

 which was used as a dwelling by the garden- 



