164 OPEN AIK GRAPE CULTURE. 



make this addition in the hotter parts of the kingdom 

 than it is here, but even here it is essential in hot 

 summers, for when the sun shines strongly on the 

 wall with a shining black surface it has appeared to 

 me to scorch those shoots which touch the wall ; but 

 this does not happen when the color is rendered 

 opaque by the mixture of the oil as recommended. 

 If the wall has not been previously colored, I give it 

 a second coat as soon as the first is dry. In laying 

 on the color care is taken that the liquid is not 

 sprinkled upon the trees, for it would close up the 

 pores of the wood and consequently do injury. 



"After the wall is colored I allow the trees to 

 remain loose from the wall until the coal tar has set 

 (unless strong winds prevail, in which case I secure 

 the main limbs and branches to the wall), in order 

 that the shoots may not be damaged by coming in 

 contact with it before it is dry. When the wall has 

 become moderately dry, I nail the trees to it. A 

 wall of sound bricks will not require recoloring 

 more than once in ten years. Coal tar being very 

 cheap, a wall of considerable extent may be colored 

 for a trifling sum. Any dark-colored paint will 

 answer the same purpose, but it is far more expen- 

 sive, and requires renewal more frequently. 



" The dark color, absorbing the rays of the sun, the 

 wall acquires at least ten degrees of heat more than 



