EXTERMINATION OF WEEDS 95 



herbicides have been made, both in this country and in 

 Europe. 



The substances experimented with by M. Girard, were 

 common salt (NaCl), copper sulphate or blue vitriol 

 (CuSO 4 ), iron sulphate (FeSO 4 ), sulphuric acid 

 (H 2 SO4), sodium nitrate (NaNOs), ammonium sul- 

 phate, (NH 4 )2SO4, potassium sulphide (K 2 S), basic 

 slag (a mixture of lime phosphate, lime sulphate and 

 some other substances), carbolic acid (CeHsOH), slaked 

 lime, and formaldehyde (CH 2 O). 



Very successful results from the treatment of weeds 

 have been reported by Sommerville, Foulkes, and Voelcker 

 of England, Steglich, Aderhold, Frank, and Heinrich of 

 Germany, and by Girard, Dusserre, Marre, and Heuse of 

 France. In this country, some of the earliest experi- 

 ments were made in 1897 by Jones and his co-workers, 

 Orton, Morse, and Edson, of the Vermont Agricultural 

 Experiment Station by destroying the hawkweed with 

 common salt. In 1898, an experiment was reported with 

 salt, copper sulphate, kerosene, potassium sulphide, 

 white arsenate of soda, and commercial weed killers. 



In 1900, Professor Bolley reported the successful treat- 

 ment of weeds with copper sulphate and later reported the 

 treatment with equal success of Canada thistle, dande- 

 lion, mustard, false flax, worm-seed mustard, corn cockle, 

 shepherd's purse, bindweed, pigweed, kinghead, red 

 river-weed, ragweed, and cocklebur. The rose was not 

 destroyed and leaves of wheat were injured but slightly. 

 The chemicals used were common salt, iron sulphate, 

 and corrosive sublimate. I reported on the effect of car- 

 bolic acid on the Canada thistle and of copper sulphate 

 and bordeaux mixture upon two types of mustard. Pro- 

 fessor Shutt and Fletcher of the Canada station also report- 

 ed the successful killing of weeds by herbicides. Wilson of 

 Minnesota reported on the use of some chemicals with 

 quack grass and found kerosene ineffectual; salt, how- 



