I : i t a ?
tendency to press into and derange that part of the groimd which acts as a fidcram.
Hence an additional reason for firmness of surface, and also for using small materials;
for if the end of a ladder, or the extremity of the foot, or any point of pressure, w ere
to exert itself on one end or extremity of a stone, it would act as a weight on the
end of a lever; and, depressing one end and raising the other end, would derange at
once the substratum and the surfiice. During rain, or when the surface of the road
was moist, this operation would go on in at least a duplicate ratio. Whatei ei may be
the weiaht of a fbur-wlicelcd caii-iage or waggon, it presses on the road on four points
only, whose united areas seldom exceed one foot; hence tho necessity of firmness, and
also of materials reduced to a size whoso areas arc less than the separate areas of the
four pressing points, in order to prevent derangement from leverage or compound action.
This subject has been ably illustrated by K, L. Edgeworth; and has been practically
exemplified, to a great and beneficial extent, by J. L. M‘Adam (Eaies f o r re p a irin g
R oads, &c. 1823), wlio has effected an entire change in the system of public load-makmg
followed in this countiy. ( S e e o u r E n c ijc . o f A g ric u ltu re .)
2396. T o resist w eather, the grand object is to get rid of siiperflnoiis water ; subterraneous
som-ces are to be cut off by drains, and surface water is not to be allowed to sink
into the road: but tbe sm-face is to be gently raised, and rendered and^ kept, by rollmg,
and continuaUy obliterating foot or machine marks, so smooth and impervious, as to
throw the water entirely to the sides. By these means, the effects of frost, heavy carnages,
and narrow wheels, are greatly lessened. , . 2397. r- i T o resist vegetation, a road mnst be in constant use ; but firmness is useful even
in this point of view, and also tho exclusion of vegetable earths from the gravels or other
materials nsed in forming the surface of garden-walks and approacli-roads. Roads
watered with strong salt water every two or three years, it is found, wdl not pioduco
weeds.
C h a t . III.
S cie ntific Processes and Operations. ^
2398 S c ie ntific processes and operations include the mastcr-operations of gardening as
an art of culture. These operations are all mechanical ; bnt some depend, for their
beneficial result, on chemical changes, as in the preparation of composts and manures;
others depend on the prevention of chemical changes, as in the preserving and keeping ot
fruits and roots ; some on imitations of climates, as in the management of hothouses ;
but the greater number are dependent on the laws of vegetable life, as in the operations
of propagating, rearing, accelerating, and retarding vegetation. Other processes _to be
treated of ai'e of a mixed natiu-c, and some depend on the laws of ammal life, as m the
operations for dcstroymg vermin and insects.
S e c t . I. P re p a ra tio n o f fe rm e n tin g Substances f o r Hotbeds, M a n u re s , an d Composts.
2399. Th e ferm enting substances used in fo rm in g hotbeds are, stable litter or dung in a
recent or fresh state, tanner’s bark, leaves of trees, grass, and the lierbaceous parts of
^ 2400^ S ta h h d u n q is in the most general use for forming hotbeds, which arc masses of
this dung after it has undergone its most violent fermentation. These masses are generally
in the form of solid parallelograms of magnitude proportioned to the frames winch
arc to be placed on them, tbe degree of heat required, and the season of the year lu winch
they are formed. , , . i j
2401. T a n n e r’s b a rk is only prefeiTcd to dung because the substance which undergoes
the process of putrid fermentation requires longer time to decay. Hence it is found
useful in the bark-pits of hothouses, as requiring to be scldomer removed or renewed
than dung, or any other known fermentable substance that can be procured in equa
^ 2402!^ Leaves, and especially oak leaves, come the nearest to hark, and have the additional
advantage, that, when perfectly rotten, like dung, they form a rich mould or excellent
manure ; whereas rotten taimer’s bark is found rather injurious than useful to
vegetation, unless well mixed with lime or sand. ,
0403 P re p a ra tio n o f manures f o r hotbeds. The object of preparation, in these three
substances, being to get rid ofthe violent heat which is produced when the feimcntation
is most powerful, it is obvious that preparation must consist m facilitating the process.
For this pui-pose, a certain degi-ee of moisture and air in the fcrmentmg bodies are
requisite ; and hence the business of the gardener is to turn them over frequently, and
apply water when the process appears impeded for want of it, and exclude ram when it
^ dimg laid on witli t e fork, raising it to t e desired
height, pressing it geutiy and equally
throughout. In general, such beds are formed
on a level surface ; but Knight’s mode
706 ) is, to form a surface of earth as a basis,
which shall incline to the horizon to the extent
of fifteen degrees; on this he forms the
dung-bed to the same inclination; and, finmly,
the frame, when placed on such a bed, if, as
is usual, it be deepest behind, will present its
glass at an angle of twenty degrees, instead
s u b i e c t , b y B i s h o p , m e r i t a t t e n t i o n
-Without enumerating the I f * '
s to c k o f g a rd en m a n u r e , such ? ? collecting ^ j ^ave practised for
soils of opposite qualities, 1 shall c o ^ e ™>seU ^ ^ situated th a t th e produce of the
these several years past with much success. ^ ^ ^ientlv be allotted for th e garden ; and this,
altnougn every way ü'-'.réré he niviiit-ips altered bv fermentation, or blended with submanure
for garden ¿ d e e d in many cases, be more injurious than beneficial. I,
stances of a heavier n a tu re , it 'youia, maeea, u ^ «ffals in the garden, such as weeds, leaves ot
therefore, during the summer and ^^^uinn fa v e all the 0^^^^^^^ t
strawberries and other vegetables, «bort g r a s s , ÎhesiTre all tèrned over, and mixed, during
shrubs when newly shed, carefully^o fCted into end of summer. 1 have
th e winter, that they may be sufficiently S L S v and cfirrln t bushes, fruit trees, raspberry
also another heap, formed with the shrubs - also the roots of greens and cabbages, which
shoots, clippings of box edgings, S t i e veaV Vfz in spring and autumn ; but, previous to
S b S n g . ’l ta ta e tv o û r ^ Pa™ up t o
U y preserve the ..ction of the fire, and / “’ r é jV a iT n 't a v c r th e heap, to prevent the fire
with safety, it is mixed up into a dungh.il
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