QUESTIONS. 285 



What is the design of the subsoil plough ? 454. Benefits of subsoil 

 ploughing ? What do recent investigations show ? 455. What is the 

 Michigan plough ? 456. What is the digger ? 457. How is the harrow 

 used ? 458. How does the cultivator compare with the harrow ? 459. 

 How is the roller used ? 460. How is it useful in laying down land ? 

 461. What caution is needed ? Effect of rolling stiff soils ? 



CHAPTER XV. 462. What conditions are requisite to germination ? 

 How does light affect germination ? 463. What is the first process ? 

 464. How does the plant grow ? 465. How does it draw food from the 

 air ? What office do the leaves fulfil ? How numerous are the breath 

 ing pores of the leaves ? 466. What do plants usually spring from ? 

 What is a tuber ? What is a bulb ? 467. What is a seed bed ? 468. 

 What do all plants require for their complete development? What 

 points is it necessary to attend ? 469. Can an imperfect seed grow ? 

 470. What is the advantage of perfect seed? 471. How may good 

 seed be known ? 472. How may the germinating power of seed be 

 ascertained ? 473. What advantage is there in learning the quality of 

 the seed ? 474. How does the vitality of seeds differ ?- -475. How can 

 the appearance of plants on new soil be explained ? 476. How is it 

 with seeds of the turnip and the grasses ? 477. What change takes 

 place in seeds? How can deterioration be prevented? 478. Why is 

 change of seed necessary ? 479. When may a change be avoided ? 

 What care is requisite to preserve the purity of seeds ? 480. What 

 common examples can be given of seeds producing fruits different 

 from those which produced them? 481. How may varieties be 

 obtained ? 482. Plow may varieties of Indian corn be produced ? 483. 

 Is a modification of the original fixed at once ? 484. How is it in cul 

 tivating potatoes ? 485. How may new varieties of the potato be pro 

 duced ? 486. Is any new variety obtained from layers, or in grafting 

 or budding ? 487. How may we judge of the quantity of seed required ? 

 488. How is the seetl required influenced by the soil ? 489. What 

 other conditions affect the quantity of seed required ? 490. How does 

 the mode of sowing affect it? 491. How is it with thin and thick sown 

 crops ? 492. When may steeping seeds be practiced ? 493. What is 

 best adapted to nourish the germ of plants ? 494. What circumstances 

 affect the time of planting ? 495. How does the condition of the soil 

 affect the time of sowing ? 496. la there any general rule applicable 

 to all crops ? 497. To what depth should seeds be covered ? 498. 

 The depth of clay and sandy soils ? 499. How does the size of seeds 

 affect the depth of covering? 500. What are some of the modes ot 



