246 EXPERIMENT STATION RECORD. 



of copper, arsenic, and lime. The season was remarkably free from potato dis- 

 eases and but little difference was noted in the yields of the different plats. 



An account is given of the treatment of the college pond with copper sulphate 

 at the rate of 1 part to 4,000.000 parts of water to clear it of bacteria and algal 

 growths. The copper sulphate was applied by placing it in a coarse bag attached 

 to a canoe, which followed concentric circles over the pond imtil the copper 

 sulphate was all dissolved. Bacterial examinations were made of the water, 

 which showed a marked falling off of the number of bacteria per cul>ic centi- 

 meter immediately after the treatment and a gradual increase subsequently, but 

 the number as long as observations were made did not attain as high a count as 

 in the original samples. Laboratory experiments with pond water were carried 

 on with practically the same results. 



A number of substances used for banding trees in connection with the gipsy 

 and brown-tail moth investigations were tested to determine their effect on the 

 trees. Many of these preparations, most of which are proprietary, contain petro- 

 leum in some form and were found to be more or less injurious to the trees. 

 The objection made to the use of some of the mixtures was found to be due to 

 the fact that they were improperly used, being applied directly to the trunk 

 of the tree in.stead of upon paper bands, as recommended by the manufacturers. 

 The authors state that of all the substances tested. Tanglefoot was the only one 

 that did not in any way cause injury to the plant tissues when placed directly on 

 the tree trunk. This substance has a high melting point, which is a decided 

 advantage for the purpose. 



The injurious effect of illuminating gas on trees is commented upon at some 

 length. 



A study is reported on the effect of soils of different texture on the gei'mina- 

 tion and growth of seeds of various kinds. The compactness of soil as affecting 

 germination and growth was tested by sowing seeds in_ boxes. In one series 

 the bdies were filled with good loam containing 8 per cent organic matter, one 

 box being tami)ed firmly and the other left very loose. In another series 2 

 boxes of subsoil of flue textui'e were employed. This soil was deficient in 

 organic matter. Lettuce, rattlebox. and white clover seeds were sown in the 

 different boxes. No lettuce seed germinated in the tamped loam or subsoil, 

 while the white clover made its appearance in the tamped loam. The rattlebox 

 seed did better than the lettuce or white clover in the soil of fine texture. All 

 of the seeds germinated better in the loose than in the packed soils. 



In another series of investigations the influence of the size of soil particles 

 was tested by seeding with lettuce. The boxes contained sifted coal ashes, the 

 particles of which varied from 0.0001 to 2 mm. in size. The highest percentage 

 of germination was given by the seed sown in ashes containing particles having 

 a size of 1 to 2 mm., while the greatest average weight of the seedlings was 

 produced in the boxes containing ashes the particles of which had a diameter 

 of 0.5 to 1 mm. In similar boxes filled with sand the highest percentage of 

 germination took place in the boxes containing sand the particles of which 

 ranged from 0.25 to 0.5 mm., while the greatest average weight of the seedlings 

 was where the particles were from 0.5 to 1 mm. in size. Attention is called to 

 the important difference between coal ashes and sand in respect to the absorp- 

 tion of moisture. 



Parallel experiments were undertaken in shallow plates containing about J in. 

 of coal ashes, having the same range in the size of particles as in the previous 

 experiment, to test the effect of aeration on germination, and the results were 

 essentially the same as in the experiment reported. 



The occurrence of plant diseases in Vermont in 1906, L. R. Jones and N. J. 

 GiDDiNGS {Vermont Sta. Rpt. 1906, pp. 227-236, figs. 2). — Miscellaneous notes 



