THE CONSTRUCTION OF PLANT HOUSES. 91 



is appareut that most of it is adulterated by the mauiifacturers. 

 Such an adulterated article might answer for sashes in dwelling 

 house windows, but its use in greenhouse work has caused most of 

 the discredit to putty glazing and should be carefully avoided. 



Painting. — For painting a greenhouse there are no better 

 materials than pure white lead and raw linseed oil. Adulterated 

 white lead and various mixed paints have been recommended and 

 used, but in the end have proved more expensive, and have 

 frequently caused serious damage to the glazing and framework. 



The paint should be applied and rubbed out thin. The priming 

 or first coat should be put on the material before it leaves the 

 factory. If heavy coats of paint are put on one over the other it 

 is likely to form itself into a separate body, become detached from 

 the wood, and, as painters say, " peel ofl." On new work for 

 commercial purposes two coats of lead are sufficient. On con- 

 servatories and private greenhouses where more attention must be 

 given to the finish of the work, a third coat should be added. In 

 this case tJie priming coat should be a mixture of raw oil and 

 whiting, yellow ochre, oxide of iron, or other pigment which when 

 applied forms no body. In such painting the preservative quality 

 is principally in the oil. All new woodwork should have an 

 additional coat after standing one year. This fills the cracks and 

 joints which are likely to open in the best work when first exposed, 

 and renews the paint which was first applied by re-supplying to it 

 the oil which has been absorbed by the new wood. 



To keep a greenhouse roof in good repair it should be repainted 

 every two years. It is safe to say that a roof which is regularly 

 and properly cared for will last twice as long as one which is 

 neglected for several years and only repaired when it must be, at 

 a greatly increased expense. 



Plant Beds. — No part of the structure requires more care in 

 construction than the benches. A bench which would be appro- 

 priate for commercial purposes, or in a growing house in the 

 kitchen garden, would disfigure a show greenhouse or conservatory. 

 A substantial and inexpensive plant table for commercial work or 

 a low priced greenhouse is made as follows : Take ordinary hem- 

 lock studs 2^ inches by 4 inches or a low quality of pine, lay one 

 line on the ground for the legs to rest on, and set up pieces of 

 the same size about two feet long and four feet apart for legs, 



