REMEDIES AGAINST THE CANKEB-WOEM. 467 



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 the 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. Mr. Jona- 

 than 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 entirely prevent the escape of the oil, 

 and the nails, with which it is secured, are found to be inju- 

 rious to the trees. These troughs ought not to be nailed to 

 the trees, but should be supported 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 becomes filled with the in- 

 sects. 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 simi- 

 lar troughs, to contain oil, around the outer sides of an open 

 box enclosing the base of the tree, and a projecting ledge is 

 nailed on the edge of the box to shed the rain ; by this con- 

 trivance, aU danger of hurting the tree with the oil is en- 

 tirely avoided. 



