196 Dr. Wallace on 
double et une flexibilité supérieure, et j’ai appris des ouvriers qui 
ont travaillé, qu’il ne fatiguait nullement les outils, tout en étant 
trés dur.” 
We may therefore await fresh investigation before considering 
the question of the value of the wood of the Ailanthus tree defi- 
nitely settled as worthless. 
I have thought it needful to go at some length into the description 
of the Ailanthus tree and its habits, for much of the success of 
Ailanthiculture in England depends on the luxuriant yet hardy and 
quick growth of this tree, and on its rapid reproduction. In planting 
with a view to Ailanthiculture, a warm sunny aspect is desirable, as 
well as shelter from the force of the wind, for I have observed that 
the leaves if exposed to a gale of wind get torn or stripped off the 
trees, and fall to the ground, carrying with them the larve, or 
that the long leaf-stalks dash against and bruise the larve, and 
further that while exposed to the force of a gale the larve are 
unable to feed, being forced to cling tightly to the leaves to prevent 
falling. Moderate winds do no harm, but some protection from 
violent gales is necessary. For that purpose I planted Jerusalem 
artichokes in a double row about every twenty yards in my 
Aitanthery (or plantation of Ailanthus trees devoted to the rearing 
of the Bombyx Cynthia), which consists of a hedge of about five 
to seven rows of trees in breadth, extending for the space of half. 
a mile along a strip of ground, about a rod wide, by the side of 
the branch to Wivenhoe from the Colchester station of the Great 
Kastern Railway. By thus interposing a series of Jerusalem 
artichokes I found a great advantage; the trees were more luxu- 
riant, cold winds were kept off, the caterpillars fed up more 
rapidly, and, in spinning their cocoons, took advantage of the large 
leaves of the artichoke and resorted thither in great numbers. It 
is recommended to plant the trees with an alley between every 
five rows, to facilitate hoeing of the weeds, observation of the 
Jarvee, and interference where necessary. In this climate on 
good soil the trees may be planted at first from two fo three feet 
apart, if on inferior soil not further apart than two feet each way 3 
the object being to afford a dense screen of foliage to the young 
silkworms, so that they can readily travel from one to another 
tree by means of the interlacing leaves. If the seed is sown 
for the purpose of forming a permanent plantation, the larvae may 
be placed on the trees in the third year of their growth; if how- 
ever two-year old seedlings are planted out, then in their fourth 
year larvae may feed on them; so that in Ailanthiculture a small 
crop may be obiained the second or third year after planting, a 
