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 Goitre gnarl of trees 378 



c. Effect of ail excess of nitrogen 387 



Over-fertilized seed 387 



Over-fertilized beets 38Q 



Over-fertilized potatoes 390 



Chile saltpetre with woody plants 391 



Over-fertilization of vegetables and other field crops 392 



Excessive nitrogen fertilization for decorative plants 393 



Leaf curl of the potato 395 



d. Excess of calcium and magnesium 399 



Excess of calcium with grapes 402 



e. Excess of potassium 403 



f. Excess of phosphoric acid 405 



g. Excess of carbon-dioxid 406 



Section 2. INJURIOUS ATMOSPHERIC IXFLUEXXES. 



Chapter IV. Too dry air 408 



Injury to buds 408 



Defoliation due to heat .411 



Honey dew 412 



Heart rot and dry rot of fodder and sugar beets 415 



Faulty development of the blossoms 416 



House plants 419 



Hard seeds in the Leguminaceae 420 



Chapter V. Excessive humidity 423 



Mode of growth with continued atmospheric humidity 423 



Influence of moist air on plants injured by drought 425 



Cork outgrowths 426 



Cork disease of the cacti 428 



Bitten or perforated leaves 430 



Formation of cork on fruits 432 



Yellow spots (Aurigo) 434 



Intumescences 435 



Tubercle disease of the rubber plant 449 



Skin diseases of hyacinths 451 



Glassy condition of cacti 453 



Chapter VI. Fog 458 



Chapter VII. Rainstorms 461 



Chapter VIII. Hail 463 



Chapter IX. Wind 471 



Chapter X. Electrical discharges 480 



Flashes of lightning 480 



Blight of conifer tops 487 



Differences between lightning and frnst w(ninds in conifers 489 



Injuries to trees in cities and towns 493 



Effect of spray lightning on grapevines 493 



Spray lightning on fields and meadows 495 



Disadvantages in electro-culture 496 



Chapter XI. Lack of heat 498 



A. General survey 498 



Life phenomena at low temperatures 498 



Autumn coloration 500 



Frosting and freezing to death 504 



Theories as to the nature of frost action 507 



Disturbances due to chilling 513 



B. Special instances of frost action 514 



Turning sweet of potatoes 514 



Running to seed of beets 516 



Frosty taste in grapes 518 



Changes in the blossom organs 518 



Rust rings in fruits 523 



