REPORT OF THE CHEMIST. 171 



Barn-yard manure is the fertilizer commonly used. This, besides furnishing nitro- 

 gen, phosphoric acid and potash, acts beneficially in improving the tilth, in supplying 

 humus, in preserving the soil moisture and equalizing the soil temperature. To 

 supply potash by means of barn-yard manure alone, excess over and above that required 

 for nitrogen and phosphoric acid must be applied, since, owing to faulty methods of pre- 

 servation, this manure is often used when partially leached out. This consideration 

 would suggest that, for the rational manuring of this crop, potash in some form (wood 

 ashes, kainit, or muriate of potash) should be used in conjunction with the barn-yard 

 manure. Wood ashes are for many reasons to be preferred ; they contain potash and 

 phosphoric acid in excellent proportions. The amount and kind of fertilizer required 

 depend very largely upon the season and the character of the soil. 



If a drought occurs during the fruiting period, a large excess of barn-yard 

 manure in the soil will prove most effective in retaining the soil moisture ; 

 on the other hand, a similar excess if the season is rainy and hot, will tend 

 to the production of foliage and runners to the detriment of the fruit crop. If a 

 soil has been devoted to strawberry culture for some years and barn-yard manure has 

 been exclusively used as the fertilizer, the probabilities are that potash and phosphoric 

 acid are the fertilizing constituents particularly needed. Consequently, wood ashes, 

 or a mixture of finely ground bone and kainit or muriate of potash, as already men- 

 tioned, should be applied. Instead of the bone meal, superphosphate may be used ; it 

 furnishes the phosphoric acid in a more or less soluble condition, but unlike bone 

 meal does not contain nitrogen. Light dressings, in the spring, of soluble nitrogen, as 

 in nitrate of soda (say 100 lbs. to the acre) are frequently of great value, especially on 

 poor soils. 



THE COPPER SALT FUNGICIDES. 



AN OUTLINE OF THEIR CHEMISTRY. 



It is unnecessary to say anything here in support of the practice of spraying ; the 

 value of certain copper compounds for the preservation of orchards and vineyards from 

 fungous foes, is every year becoming better known and more widely appreciated. Ad- 

 vanced orchardists the world over recognize the efficacy of the copper fungicides for 

 keeping both foliage and fruit clean and free from injurious attacks. 



That the mixture or solution used may be effective in fungicidal power, as well as 

 non-injurious to foliage, two factors must be paid attention to : — (1) the right prepar- 

 ation of the fungicide, and (2) the earliness and frequency of application. It is the 

 first of these only that we shall consider here. 



As may have already been inferred, the efficacy of the fungicides is largely depen- 

 dent upon their chemical composition and physical condition. These in turn are depen- 

 dent upon the materials and the method of manufacture used. We may further state 

 that a correct and intelligent preparation of the solutions and mixtures necessitates a 

 knowledge, at least in outline, of the changes that take place under varying circum- 

 stances of manufacture. The account of these reactions which follow, though necessar- 

 ily brief, will place the reader in possession of facts of great assistance for effective 

 spraying. 



Bordeaux Mixture. 



The source of the copper in all spraying preparations is primarily copper sul- 

 phate, commonly known as bluestone— a deep blue crystalline salt, easily soluble in 

 water, the chemical formula of which is CuS0 4 , 5H 2 0. 



