215 



(3) That all varieties of spring wheat are nureliable iu Iowa, and should be dia- 

 carded ou account of their liability to attacks of rust. 



We cau not speak positively iu regard to winter wheat ; but the results of our exper- 

 iments indicate that the hardiest varieties may be grown successfully ou well-draiued 

 soils if they are mulched sufficiently to prevent the ground' froni thawing during the 

 drst warm spells iu the spring. There is no better mulch than a dense growth of wheat 

 blades, which can bo secured generally by sowing wheat about the 1st of Septem- 

 ber in the northern half of the State, and a little later farther south. The Turkish 

 and Golden Cross arc -the most reliable varieties of winter wheat which we Lave 

 tested. 



Experiments with arsenites, C. P. Gillette, M. S. (pp. 401- 

 420), — This iirticle is substantially the same as a paper read by the 

 author before tlie Society for the Promotion of Agricultural Science, at 

 lntliauai)olis, 189t). It includes a report ou experiments made during 

 the past two seasons, in which much attention was given to the findiug 

 of some method of applying the arsenites "so as to prevent injury to 

 foliage without lessening their effectiveness in destroying insect life." 

 There are also given results of experiments, the object of which was to 

 observe the relative injuries to foliage from applications of the arsenites 

 when freshly mixed and when allowed to stand a few-days before being 

 applied; the effects of adding paste or soap to arsenical mixtures; the 

 eff"ects of sun, dew, and rain upon foliage treated with arsenical mixt- 

 ures; whether or not it is practicable and safe to mix the arsenites with 

 insecticides that kill by external contact, and the efffects of combining 

 the arsenites with fungicides. 



In these experiments more than one thousand applications were made, 

 in most cases " to a few carefully selected twigs, bearing perfect foliage, 

 where every leaf could be thoiouglily treated. Most of the applications 

 have been made with a bellows-sprayer or atomizer." Among sources 

 of error apt to be overlooked in calculating the results of such expeii- 

 ments are noted the age of the leaves, injuries due to fungi, position 

 and shape of the leaves, and effects of rain, dew, and sunlight. 



Comparative injuries to foliage from London purple, Paris green, and 

 ichite arsenic, when freshly mixed and applied in water. — Data for ex- 

 periments on plum, apple, cherry, peach, alder, and poplar trees are re- 

 corded in a table. 



It will be seen that in the proportion of 1 pound to 25 gallons. the average injury 

 from London purjjle has been 4G, from Paris green 37, and from arsenic 8 per cent. In 

 the proportion of I pound to 50 gallons, London pnrple has averaged 30, Paris green 

 30, and arsenic 1 per cent injury. In the proportion of 1 pound to 100 gallons, London 

 pur[)le has averaged 15, Paris green 9 per cent, and white arsenic no injury. In the 

 proportion of 1 pound to 'iiOO gallons, London purple has averaged 7, Paris green 3 per 

 cent, and white arsenic no injury. It will also be noticed that ditferent trees vary 

 greatly in their power to resist the action of these poisons. In my experiments, aider 

 and poplar have not been seriously injured by ai)i)licationsa8 strong as 1 pound to 25 

 gallons. Cherry has been less injured than apple, and apple less than plum, wIhIh 

 peach has been most susceptible of injury of any plant to which the poisons were 

 applied, a pound to 200 gallons in some cases destroying more than 50 per cent of the 

 foliage. 



Perhaps the most surprising thing set forth in the table is that pure white arsenic 



