364 IXSECTS INJURIOUS TO VEGETATION. 



a public square, but will be found too expensive to be applied 

 to any great extent. Collars of tin-plate, fastened around the 

 trees, and sloping downwards like an inverted tunnel, have 

 been proposed, upon the supposition that the moths would not 

 be able to creep in an inverted position, beneath the smooth 

 and sloping surface. This method will also prove too expen- 

 sive for general adoption, even should it be found to answer 

 the purpose. A belt of cotton-wool, which it has been thought 

 would entangle the feet of the insects, and thus keep them from 

 ascending tiie trees, has not proved an effectual bar to them. 

 Little square or circular troughs of tin or of lead, filled with 

 cheap fish oil, and placed around the trees, three feet or more 

 above the surface of the ground, with a stuffing of cloth, hay, 

 or sea-weed between them and the trunk, have long been used 

 by various persons in Massachusetts with good success; and 

 the only objections to them are the cost of the troughs, the 

 difficulty of fixing and keeping them in their places, and the 

 injury suffered by the trees when the oil is washed or blown 

 out and falls upon the bark. IVIr. Jonathan Dennis, Jr., of 

 Portsmouth, Rhode Island, has obtained a patent for a circular 

 leaden trough to contain oil, offering some advantages over 

 those that have heretofore been used, although it does not en- 

 tirely prevent the escape of the oil, and the nails, with which 

 it is secured, are found to be injurious to the trees. These 

 troughs ought not to be nailed to the trees, but should be sup- 

 ported by a few wooden wedges driven between them and the 

 trunks. A stuffing of cloth, cotton, or tow, should never be 

 used ; sea-weed and fine hay, which will not absorb the oil, 

 are much better. Before the troughs are fastened and filled, 

 the body of the tree should be well coated with clay paint or 

 whitewash, to absorb the oil that may fall upon it. Care 

 should be taken to renew the oil as often as it escapes or be- 

 comes filled with the insects. These troughs will be found 

 more economical and less troublesome than the application of 

 tar, and may safely be recommended and employed, if proper 

 attention is given to the precautions above named. Some 

 persons fasten similar troughs, to contain oil, around the outer 

 sides of an open box enclosing the base of the tree, and a pro- 



