LIFE OF JAMES DWIGHT DANA 



be thrown out by the winds, and it is also quite unneces- 

 sary if the troughs receive proper attention afterwards. 

 Poor lamp oil, if the above rules are regarded, is prefer- 

 able to the best, since it is thicker, and therefore not so 

 easily displaced. 



" Although oil is a sure means of protection from the 

 canker-worm, there is an obvious objection to its use in 

 the danger in windy weather to the clothes of those pass- 

 ing beneath, and it is desirable that ingenuity should be 

 set to work toward devising something better. Mr. E. 

 Hayes, printer, uses for his apple trees a refuse printing- 

 ink with perfect success; and if a material of like nature 

 could be made at a moderate price it would be all that 

 could be desired. He puts around the tree a girt of stout 

 brown paper, about ten inches wide (tying it on with a 

 string), and then besmears the paper with the ink. The 

 material is not removed by moisture or rain, and, unlike 

 tar, retains its adhesiveness for two or three months 

 through all kinds of weather, and only requires occasional 

 attention to see that the moths have not so filled it with 

 their bodies as to make a safe way for others. Printing- 

 ink consists chiefly of boiled and burnt linseed oil with 

 rosin and lampblack. The lampblack is not essential 

 for the purpose here in view. 



" Some readers may be interested to know that the 

 canker-worm miller belongs to a group under the butter- 

 fly division of insects, called geometers a term that alludes 

 (like that of measure worm, sometimes applied to the 

 canker-worm) to the mode of locomotion of the worms. 

 And in this group it pertains to the genus anisopteryx 

 so named (from the Greek) because the males and females 

 differ as regards the wings." 



TO SPENCER F. BAIRD 

 The National Academy of Sciences. Death of Silliman. 



" NEW HAVEN, Dec. 10, 1864. 



11 As the time for our January meeting of the National 

 Academy approaches, I become more and more convinced 

 that I ought not to encounter the labor and fatigue of 

 the occasion, Had I no duties but those of a private in 



363 



