1817.] 



AND HORTICULTURIST. 



27 



be nearly worn out, are still to be found as pro- 

 ductive as ever tbey were. At the present mo- 

 ment we have in the fruit-room, samples of Rib- 

 stone Pippin apple as fine as one could wish to 

 see ; the Golden Pippin apples, from old trees, 

 are still as satisfactory as ever; the old Forge 

 apple is another variety which still holds its own 

 against all comers for productiveness. As these 

 facts are undisputable, I cannot understand what 

 sound argviments in favor of the wearing-out 

 theory can be brought forward." 



Absorbtive Power of Clay. — It is now well 

 known that clay has the power, when dry, of 

 absorbing ammonia from the atmosphere. It is 

 the principle of what is known as the earth 

 closet system. There is no longer any question as 

 to where the earth gets its nitrogen. Dr. Joseph 

 Leidy has now made the additional and import- 

 ant discovery that wet clay as well as dry, has 

 absorbent powers. In a verbal communication 

 to the meeting of the Philadelphia Academy of 

 Natural Sciences Oct. 31st, he detailed some 

 ■dredging experiments made below the gas-works 

 on the Schuylkill river, and found the mud in 

 the bed of the river highly charged with bitumi- 

 nous matter, evidently from the gas-works. As 

 oil floats, of course it became a question how it 

 got to the bottom, and Dr. Leidy says that the 

 oil combines with the clayey particles in the 

 water, and thus both sink together. In this way 

 he thinks many geological problems may be 

 solved. The oils of decomposing plants and ani- 

 mals have no doubt given the bituminous char- 

 acter to the ancient muds and shoals very often 

 in a similar way. 



QUERIES. 



Horticultural Science. — A correspondent 

 says : — " Will you please note down some of the 

 experiments in Horticulture which you think 

 are most needed, to be tested thoroughly. It 

 will need some thought, but you can print the 

 list; then your time will not be wholly lost." 



[A very useful experiment would be the bot- 

 tling, or in some way burying beneath the sur- 

 face of the earth, seeds of acorns, nuts, or other 

 seeds, several lots of one kind to be taken up at 

 different periods, so as to know something about 

 the vexed question of the vitality of seeds, and 

 the succession of plants in forests. We want 

 many more experiments on Graft hybrids, by 



splitting scions, or summer buds ; or in uniting 

 tuberous plants on fibrous ones, or the reverse. 



Bulbs placed in the ground several inches deep 

 and at once encased in frozen soil, have grown to 

 the surface when the first thaw corner Just 

 how much they grow when frozen, and their 

 whole course of growth through the frozen ground 

 would be interesting. Kerner says, in the Alps, 

 some Gentians grow and thaw for themselves a 

 house in the ice, and flower therein— it might 

 not be impossible to repeat some such experi- 

 ments, and the result would teach us much about 

 the internal heat of plants. 



Honeyed secretions appear to be given to plants 

 for the purpose of furnishing a nourishing liquid 

 to pollen. The surplus — as there always is a 

 large surplus in all nature does — being freely at 

 the disposal of the insect world. At any rate the 

 pollen tube is only emitted when there is a hon- 

 eyed secretion on the stigma, and it is said that 

 flowers which do not seed are made to do so by 

 applying nectar artificially. Experiments would 

 be useful — as well as many other experiments in 

 relation to fertilization. Can any one make 

 Amaryllis fulva, seed? 



Whether the same amountof heat is given out 

 to a greenhouse from a ton of coal, when heated 

 by hot water, as when heated directly from a 

 flue — and if not, how much is lost? 



These are some of the problems that occur to 

 us, as we write. There are many more which 

 might come from reflection, which correspon- 

 dents might suggest and which we should be 

 glad to note in these columns. — Ed. G. M.] 



Tree Growth. — M. H. D., Detroit, Mich., says: 

 " In an argument with a friend to-day, we agreed 

 to leave the following question to you for con- 

 sideration : ' Do fruit or forest trees grow after 

 the leaves drop in the Fall, or before the sap 

 rises in the Spring ? ' My friend says they do, I 

 say they do not." 



[Practically the answer is in the negative. No 

 one would be able to perceive the slightest dif- 

 ference in girth, at any time between the peri- 

 ods named. Yet there may be growth of some 

 character at such times. Gardeners know that 

 a " callus," a cell growth, forms on the ends of 

 cuttings, and often roots of a considerable length, 

 before any leaves appear; and after the leaves 

 fall, fibres of trees grow, many believe all through 

 Avinter, and to some extent even when encased 

 in frost. In the Spring, when the buds are push- 

 ing, there is often considerable growth before the 



