373 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, September 20. 1859. 
for us to give even an epitome of the work; hut the following 
■extracts will furnish our readers with some idea of the manner in 
which the subject is treated:— 
“ Most persons, perhaps, have seen a chalk country—a district 
in which the subsoil is chalk. This part of the cretaceous 
formation—chalk, properly so called—which attains in some 
places a thickness of many hundred feet, may be separated into 
two great natural divisions—the upper and the lower chalk. Of 
these the upper is much the softer. It is this which is used as a 
material for writing upon school-boards, and for other similar 
’ purposes. This upper or soft chalk is found marked out into 
strata, as it were, by layers of flint. Sometimes this flint, which 
; is usually only a few inches in thickness, occurs in an unbroken 
I sheet; but its prevailing condition is that of nodules—lumps of 
a more or less rounded form, though often of a shape so irregular 
and grotesque as to have made them a favourite ornament in 
cottage gardens, where they may be seen neatly whitewashed as 
edges to the flower-borders. If these chalk flints be broken, we 
shall find the inside of them agreeing with the pebbles of' our 
surface soil and gravel pit3, not only in general appearance, but 
in fossil contents: we shall see in them the same animal remains, 
in the same condition, and in the same relative proportions— 
those species which are the most common in the stones with 
which we are so familiar, being likewise most abundant in chalk 
flints. In Bhort, we cannot entertain a doubt that the one kind 
of stone has some close relation to the other.” 
* * # * * 
“ We shall, of course, wish to know the origin of the flint in 
the chalk, and under what circumstances it enveloped, and often¬ 
times converted, as it were, into its own substance the organisms 
of which it laid hold ; for it will be found that, not only many of 
the fossils that are inside the flints, but some of those that adhere 
loosely to their white outside coating, have parted with their 
lime and have appropriated siliceous matter instead. These are 
questions which have been answered in different ways—always 
eonjecturally, for no satisfactory proof has as yet been offered to 
show that any of these solutions of the difficulty is the right one. 
* * * * Some geologists and chemists, indeed, suppose that 
chalk flints in general are zoophytes fossilised by silica; and that 
the more carefully the flint nodules are examined, the more 
frequently will traces of organisation be found in them.” 
Such, then, is Mr. Eley’s reply to our question, What is a 
flint ? We have selected it from detached paragraphs merely for 
the purpose of illustrating the higbly-intelligible way in which 
the information is communicated: but the subject is a lengthy 
one, and our space does not permit us to enter more fully into it 
than we have done. Suffice it to say, that we have derived both 
pleasure and profit from the perusal of this nicely got up, ad¬ 
mirably written, and well illustrated volume ; and to those of our 
readers who know nothing of the subject, as much as to those 
who know something, we recommend it as one of the most read- 
I able books on science popularised that we have ever met with. 
Eabm Insects.*— Next to a knowledge of vegetable physiology 
and chemistry, there is no subject that more requires the attention 
of the gardener and farmer than entomology. When we consider 
the myriads of insects which derive their support from the culti¬ 
vated plants of the garden and farm, in many instances entirely 
devouring whole crops, it becomes a matter ot absolute necessity 
for those most interested to make themselves acquainted with 
their forms, transformations, and habits. In the work before us 
we have the subject treated most fully, both scientifically and 
practically, by a gentleman who has tor a long period devoted 
his attention to the study of insects, and who is justly associated 
among the most eminent modern entomologists. The two, parts 
of the work already published ace devoted to the insects affecting 
the Turnip and Cabbage crops ; and include the Turnip saw-fly, 
plant lice (aphides), maggots of flies, surface caterpillars, Turnip 
gall-weevils, and rove beetles. Every species is separately de¬ 
scribed ; their transformations, many of which are most inter¬ 
esting, are minutely related ; and in many instances the texu is 
illustrated with excellent woodcuts of the insects in then’ various 
stages of development. The work is also illustrated with beautiful 
steel engravings from the drawings of Mr. Curtis himself; and 
having said this much, we feel we are giving an assurance that 
the work will be ably carried out. It should be in the hands of 
all cultivators of the soil. 
* Farm Insects : being the Natural History and Economy of the Insects 
injurious to the Field-crops of Great Britain and Ireland, By Joan 
Curtis, F.L.S. London : Blackie & Son. Parts I. and II. 
VARIETIES. 
Antiseptics are substances which arrest the putrefactive 
changes that dead vegetable and animal matter is liable to undergo 
when exposed to air, warmth, and moisture. Antiseptics are, 
therefore, antiputrescents ; and the term itself indicates the office 
which the members of 'the class fulfil {anti against, and septikos pu¬ 
trefactive). The theory of the action of all antiseptics is, that one 
or two of the three indispensable conditions of putrefaction—viz,, 
1, a moderate warmth, 2, access of air, and 3, moisture, are 
arrested or neutralised. Tims, in the preservation of fish in stores 
or during transport by railway, they are packed in barrels with 
ice, which keeps down the temperature; and though air and 
moisture gain admittance, yet the putrefactive processes cannot 
proceed. The same preservative power of cold is observed natu¬ 
rally in the discovery of remains of elephants and other animals 
imbedded in the ice of the polar regions, and which, doubtless, 
have been locked up there for ages. In a less degree, the influ¬ 
ence of cold as an antiseptic is observed in the longer time that 
meat-, eggs, and other animal matters keep fresh in winter than in 
summer. Again, warmth and moisture may be present, but if 
the air be excluded putrefaction does not go on. The ordinary 
mode of preparing preserved meats affords the best illustration of 
this point. The substance to be preserved is placed in a tin dish 
covered over, and leaving a very small opening. When the can 
with its contents is heated, the air which fills up the pores of the 
solids, and is dissolved in the liquids, is driven off, and, escaping 
by the aperture in the cover of the dish, leaves the contents 
devoid of air. If the opening be now closed with solder, the air 
is kept from returning ; and whatever climate the can of preserved 
meat be sent to, yet so long as the tin casing remains good, and re¬ 
fuses to admit the air, so long will the contents continue wholesome 
and palatable. The common plan of preserving eggs by rubbing 
over the shell with tallow or oil, is founded on the principle of 
filling up the pores of the shell, so as to deny the admission of 
the air. Moisture is likewise necessary for the process of putre¬ 
faction. Thus, if the contents of an egg be thrown out on a 
plate, and thoroughly dried in an oven, the whole becomes of a 
hard, horny consistence, and may be kept in this state for years 
without exhibiting the slightest symptom of passing into a putre¬ 
scent or rotten condition. In the same way meat may be kept 
quite fresh by depriving it of moisture. Eggs dried up in this 
manner require only to be soaked in cold water, and then boiled, 
when they will present themselves in a condition hardly differing 
in flavour and taste from an ordinary boiled egg. The more im¬ 
portant chemical antiseptics are—Alcohol, wood-spirit, creasote, 
pitch-oil, coke-oil, sugar, tannic acid, sulphurous acid, common 
salt, nitre, alum, chloride of zinc, sulphate of copper (blue 
vitriol), corrosive sublimate, arsenic. The manner in which these 
antiseptics act is very different.—1. Sulphurous acid acts by 
combining with the oxygen, and thereby deoxidising the sub¬ 
stance. 2. Syrup of sugar acts by combining with the water of 
the substance to be preserved. 3. Creasote, tannic acid, alum, 
chloride of zinc, sulphate of copper, corrosive sublimate, and 
arsenic, are useful in forming compounds with the organic matter, 
which are not so liable to become putrescent as the uncombined 
organic substance. 4. Alcohol, wood-spirit, common salt and 
nitre act in a double way, by combining with^ the water of the 
putrescible substance, and by combining with the substance 
itself, so as to form a more durable compound. Some of the 
more important uses to which the chemical antiseptics are ap¬ 
plied are—1. In the preservation of anatomical specimens, where 
alcohol, and less often, chloride of zinc, are the agents ; 2. In the 
curing of herring and other fish, where common salt is genei ally 
used ; 3. In preparing corned or salted meat and tongues, where 
common salt and nitre are jointly employed ; and 4 In the ma¬ 
nufacture of size for writing-papers, where the paper-maker uses 
sulphite of soda or antichlore (containing sulphurous acid) to 
arrest the decomposition of the scraps of hides used in the ma¬ 
nufacture of size. In the preservation of timber, antiseptics are 
also taken advantage of. The wood is placed in a steam-box, and 
the air contained hi its spores being replaced by steam, the whole 
casing is closed tight, and allowed to cool, when the steam con¬ 
denses, and leaves a vacuum in and around the block of the wood. 
On the introduction thereafter of one of the antiseptics, it finds 
its way into the innermost pores of the timber. Mood thus 
prepared is not nearly so liable to decay as it ordinarily is ; and 
the antiseptics seem to act here not only directly in withdrawing 
water, and forming durable compounds, but in offering a poison¬ 
ous dose to minute plants and animals which tend to house 
themselves in the wood. The use of sulphate of copper lor this 
