7$ 



On the Culture of the Pine Apple. 



the back wall, would not exceed four-pence a day. A roof, 

 of properly curved iron bars, appears to me also to present 

 many other advantages : it may be erected at much less 

 cost, it is much more durable, it requires much less ex- 

 pense to paint it, and it admits greatly more light. 



I have not yet been troubled with insects upon my Pine 

 plants, and have not, of course, tried any of the published 

 receipts for destroying them. Mr. Baldwin recommends 

 the steam of hot fermenting horse-dung :* I conclude the de- 

 structive agent, in this case, is ammoniacal gas ; which Sir 

 Humphry Davy informed me he had found to be instantly 

 fatal to every species of insect ; and if so, this might be ob- 

 tained at a small expense, by pouring a solution of crude 

 muriate of ammonia upon quick lime ; the stable, or cow- 

 house, would afford an equally efficient, though less de- 

 licate fluid. The ammoniacal gas might, J conceive, be 

 impelled, by means of a pair of bellows, amongst the leaves 

 of the infected plants, in sufficient quautity to destroy 

 animal, without injuring vegetable life : and it is a very in- 

 teresting question to the gardener, whether his hardy enemy, 

 the Red Spider, will bear it with impunity. 



* Baldwin's Practical Directions, &c. page 30. 



