THE LEAD-CABLE BOKER IN CALIEOENIA. 29 



while others did not. In none of the eases observed were any beetles 

 found that had made an attempt to enter the cable. As a matter of 

 fact, they paid no attention whatever to it. Painting it with fresh 

 and old oak-bark tea and other substances seemed to haA^e no effect 

 on them as long as they had the large cages in which to fly. They 

 walked on the P. & B. paint and the pine tar soon after they w^ere 

 applied without getting stuck. 



Numerous beetles w-ere then placed in small cages which confined 

 them closely to the cables. These also failed to attack except in one 

 case where the cable had been painted with a tea made from fresh 

 oak bark and kept in a tight jar for some time. Eighteen beetles 

 were placed in this cage and fifteen attempts to penetrate the cable 

 were found. Five of these were one-fourth to one-half penetration 

 and the others less than that. 



During this same time numerous beetles entered an oak stick 

 that was placed in the large cage, which indicated that they were 

 in the proper stage of maturity to make the experiment practical. 



Service cables. — Five hundred and sixteen beetles were placed in five 

 small cages on the service cables in Los Gatos. One of these cages in- 

 closed rings and marline ties and the screen was not close enough to the 

 cable for the beetles to attack anywhere but at the rings; the other 

 cages were between the rings, and the screen w^as close enough to the 

 cable so that the beetles could attack from any point. One of these 

 cages was painted with black paint to see if this would give a better 

 foothold, but it proved a failure. One hundred and twenty-nine 

 beetles were placed in the first cage, v^hich allowed for the regular 

 attack to be made at the suspension rings or marline tie. None made 

 any attempt on the cable. Three hundred and seventy-six beetles 

 were placed in the other three cages, where an attack could be made 

 at any point. In all three of these, attacks on the cable were made, 

 5 in one, 11 in one, and 7 in the third, or a total of 23 attacks. Of 

 these only 1 went completely through the sheath, 6 bored from one- 

 third to one-half through, and the others made only slight impres- 

 sions in the lead. 



Note. — To get an idea of the ease of applying various substances 

 to the cables, the following cooling tests were made. In each case the 

 material was heated to a liquid state and then left standing until it 

 hardened again. 



Beef tallow Hardened in 1 hour, 10 minutes. 



Refined paraffin Hardened in 20 minutes. 



A chlorinated naphthalene compound, No. 1001 Hardened in 10 minutes. 



A chlorinated naphthalene compound, No. 1008 Hardened in 7 minutes. 



This indicates that the tallow would be much more easily applied 

 than any of the other compounds that would soften under the heat 

 of the sun. 



