Page images
PDF
EPUB

in this Paper more nearly than the Irish form approaches the Venetian type. The Portuguese variety differs from the type, both in the matter of size and in the more closely approximating setae. The examples preserved in alcohol are 40 to 50 mm. in length, with a maximum diameter of 3 mm. For the rest, the colour, position of girdle, tubercok, and spermathecse, it is exactly like the type. This variety, says Dr. Rosa, in a recent bulletin which he has courteously forwarded to me, is precisely the same as Miehaelsen's forma hortensis, which Boss, through the kindness of Michaelsen, has carefully examined.

It is true that, so far as the tubercula and spermatheca are concerned, the Irish and Venetian worms are alike, and it may be possible, when our knowledge is wider, to decide whether or not the foregoing are distinct species, sub-species, forms or varieties of one another. In the meantime the differences in size, colour, shape, disposition of setae, and the like must not be overlooked. The Irish worm is, in general appearance, closely allied to the mucous worm {A. mucosa, Eisen), while the Venetian is identical with the brandling. Rosa has recently described a new Tunisian worm {A. besta, Rosa) which in some points touches cm Irish worm, and links it with the Venetian species. Its length is 30 to 35 mm., and its diameter 2 mm. in alcohol. The form is cylindrical, the prostomium extremely small, and often entirely retracted into the buccal cavity. The tubercula are on 29 : 30 : 31, as in the mnconf worm (A. mucosa, Eisen), and the spermathecaj are in two pain, opening dorsally in segments 12 and 13. Rosa would have taken it for a form of the mucous worm if he had not examined the latter character, and rightly insists upon the absolute necessity of observing the number, position, and direction of the duct of the sperm-saes.

Postscript.—A few weeks after the discovery of the worm described in the foregoing communication, an account of which I sent to Dr. Rosa of Turin, I learned from that distinguished savant that he had simultaneously discovered a new worm in Italy which exactly corresponded with my account of A. hibernica. To this animal he at first assigned the position of a variety merely, and proposed for it the name of Allolobophora veneta, Rosa, var. decolor. He has since suggested that it be known as A. cantibrica, Rosa, but I do not know whether he has published any account of the worm under that name or not. We have exchanged specimens, and I have every reason to believe the worm found in Geneva to be identical with that discovered in Dublin.

XXVII.

S'OTES ON NEWTONIAN CHEMISTRY. By REV. SAMUEL HATJGETON, M.D., S.F.T.C.D.

[Read April 11, 1892.]

Note II.—Ternary Compotods.

(Water Type.)

Ik my first note on compounds of the hydrochloric acid type (HC1), I showed that the properties of the Halogen group, when combined with hydrogen, could be explained on Newtonian principles, viz.,

[merged small][graphic]

where y. is the coefficient of attraction, varying with the chemical nature of the compounds, m, m the atomic weights, and r the distance of the bodies.

At all sensible1 distances the coefficient of attraction (ji) is constant; but at insensible distances such as those contemplated in Chemical Science, /* ceases to be a constant, and varies with the chemical nature of the element, and varies also from other causes, as I shall demonstrate in this note.

By equating the centrifugal force to the attraction in any molecule the radius of whose orbit is unity, we found

_ 4<o« _ 4

where u is the angular velocity, m the reciprocal of u>, and /? the atomic weight.

'In sensible distances I include the smallest distances made known by the microscope.

H.I.A. PBOC., SEB. m., VOL. II. 2 X

Using the values found in Note L we construct the following Table:—

Coefficient* of Attraction.

[table]

This Table Bhows how enormously the coefficient of attraction of hydrogen exceeds those of the halogens.

In the case of hydrogen combined with one of the halogens, by equating the centrifugal force to the attraction, we obtain

where /? is the atomic weight, and m the reciprocal of the angnitf velocity of the halogen molecule, and n' the coefficient of attraction between hydrogen and the halogen.

Using the values found in Note I. we construct the following Table, remembering that the values of m must be negative: —

[merged small][table]

1. Case of Water (H,0). In the case of water, two atoms of hydrogen are united to one atom of oxygen to form a molecule, and we must suppose that two molecules of hydrogen unite with one molecule of oxygen, with the result that the oxygen molecule is bisected, and that we have two molecules of water. The molecular volume of oxygen is the same as that of hydrogen, and (as is well known) the volumes of hydrogen and oxygen in becoming steam are reduced to two-thirds of the bulk of the original volumes.

The volume of the water (steam) molecule is the same as that of the hydrogen, fluorine, chlorine, bromine, iodine, and oxygen molecules,

for

weight

18 molecular volume =

specific gravity 0.622 = 28.94, a result strictly comparable with those already given for the molecular volumes of the elements named.

Before discussing the ternary compound of one atom of oxygen united with two atoms of hydrogen, let us consider the binary compound of one atom of oxygen with one atom of hydrogen. This binary compound is not known to exist separately, but is recognized in combination in complex bodies and is called hydroxyl. The reason why it is not formed separately is, that it is less stable than water,

H2O > HO,

i Vide Appendix.

2 Hydroxyl. As a matter of fact, OH is not known in the free state, but is recognized by chemists as existent in numerous chemical compounds. All oxyacids are supposed to contain one or more OH groups, and the caustic alkalies, potash, soda, &c., contain OH also ; while peroxide of hydrogen (H2O2) is regarded as an unstable compound of two OH groups which are tacitly assumed to be more or less opposed in properties.

This, as I shall show, is in entire accordance with the principles of Newtonian Chemistry.

An investigation of the properties of HO similar to that of the properties of HCl, in Note I., would give the rotations and stabilities of these two hydroxyls,

[ocr errors]

positive hydroxyl, . w'= + 0.97017.

negative hydroxyl, . W = - 110406, revolving in opposite directions, and having stabilities,

positive hydroxyl, . w'2 = 0.94123,

negative hydroxyl, . w'2 = 1.2189 ; not far from the proportion of 7 to 9.

and is thus prevented from making its appearance as a separate empound.

If we look back to the dynamical equations on which hydrochloriE acid depends we have

Area* (fi + 1) «' = 0 (1 + fa). (4)

Energy (1 + fa*) - a)" = 0. (5)

P

If we substitute in these equations for /? the atomic weight of oiygea we have the conditions necessary to account for the production of hydroxyl.

In equations (4) and (5) I have supposed the atoms to be fofinitelT hard, elastic, and without rotation, so that they cannot undergo any change of energy during collision, and that the whole ebsng-t of energy takes place in the orbital changes of the molecules.

If we suppose this to be no longer the case, and that ± c, denote the atomic loss or gain of energy in forming one molecule of hydroiyl we have, instead of equation (5),

2c,+ (1 + fa*)- ^-^co* = 0. (5) to

Eliminating <u' between (4) and (5) bis, we find, after some reductions, and making &>, = —

m

(2(0 + 1) c, + 1 Jm» - 2fJ>m- {p> - p-p) = 0. (7) Ut.

Substituting for /J the atomic weight of oxygen, we have

(34c, + 1) ms - 512m - 3824 = 0.

If the atoms of oxygen and hydrogen have no rotation, and be infinitely hard and elastic, c, = 0, and the value of m becomes

m =- 7-3625.

If we take (as in Note I.) the nearest whole number and make

m= -7,

we find,1 as the most probable solution,

o>"= 1-2564, a, = 1-50, e, = + 0-0042,

where c, represents the atomic loss of energy, per atom of hydrogen, during the formation of hydroxyl, and a/* represents the stability of hydroxyl.

1 See Note A, p. 430.

« PreviousContinue »