40 EXPEKLMKXT STATION. [Jan. 



roots which jittoinj)(e(l to untw in excelsior were l)rowne(l and 

 dead. The results obtained from the nse of cocoa fiber and 

 creosote were not nearly as good as the two preceding ones. The 

 roots penetrated the fiber and came through into the water. 

 About 35 per cent, of the roots which penetrated the fiber were 

 alive and healthy. 



The results obtained from the untreated oakum showed that it 

 had little efieet, ihe roots appearing to be healthy, and not at all 

 injured by this substance. 



B. — The experiments described here were made in three 

 boxes, each being 1-i inches wide, 22 inches long and 14 inches 

 high. The bottoms of these boxes were covered with l/4-inch 

 mesh galvanized wire. On each wire in (me-half of each box 

 there was placed about 1 inch of sphagnum, the other half being- 

 covered with some treated material. Box Xo. 1 had sphagnum 

 1 inch thick in one end and the same amount of excelsior treated 

 with creosote in the other end. Box Xo. 2 was likewise pro- 

 vided with untreated sphagnum in one end, the other being filled 

 with sawdust treated with cement. Box Xo. 3 was treated in 

 the same way as Xo. 1. These boxes contained about 12 inches 

 of soil, and rested on galvanized-iron trays containing 2 inches 

 of water. A space of about half an inch, however, was left be-: 

 tween the bottom of each box and the water in the tray for the 

 purpose of observing the roots. Several crops of tomato and 

 tobacco plants and grass were grown in these boxes, with the 

 results that none of the roots had penetrated through the treated 

 substances into the water in the tray, whereas in every case 

 where untreated sphagnum was employed the root penetration 

 was invariably common. 



The results obtained from these various methods of treatment 

 show that it is possible at the present time to prevent root growth 

 by the use of certain chemical substances. Our residts seem to 

 indicate, also, that these various treatments possess a lasting 

 effect, and that chemically treated fibers could be used in a 

 practical way to prevent the clogging of drain tile. In these 

 ex]ioriments it nmst bo boruo in mind that n vast nund)er of 

 roots come in contact with the treated substances, and that ordi- 

 narily if these substances had not been there thousands of roots 



