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least water was formed, with the observance of certain precautions, at the boiling point. This throws out a hint with reference to the possibility of obtaining other salts of magnesia as well, wherein the quantity of water varies.

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The combinations arrived at by the chemists here named, correspond to the quantities of oxygen stated below:

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4

This is an approximation to the formula Mg C3+4, according to which the oxygen ratio should be 26-39: 17-59: 17.59. Apparently, therefore, the water contained in carbonates of magnesia constituted as above, either does not act the part of a base at

* See Gmelin's Handbuch der Chemie, New Edition, vol. ii, p. 224.

all, or does so only to a small extent; possibly the latter may often obtain with regard to some of the salts quoted towards the end of the above group. We have for instance, in the case of salt No. 9, the oxygen ratio 26-33: 16-29: 19.30, whereas it ought to be 26-33: 17.56: 17.56. Possibly, therefore, in this compound 1.27 Mg (that is to say 17·56÷16·29), are replaced by 1.74 (namely 19:30-17.56), which would be exactly in the ratio required. On enquiring how it is that in fourfold hydrated three-fourths-carbonate of magnesia, no magnesia, or at least very little, is replaced by basic water, the two following circumstances offer themselves in reply. 1. The ten salts that we have mentioned were one and all, obtained at a boiling heat. 2. It must evidently be more difficult (from the reasons which I have entered into in the preceding paper relative to the kindred circumstances applicable to aspasiolite and serpentine) for water to find its way into a three-fourths-carbonate than into a semi-carbonate and expel from thence a portion of the magnesia.

In addition to the hydrous magnesian carbonates here mentioned, amounting in all to seventeen, which may be ranged in the two groups above described, there are other five that have been analyzed, one of which however may be omitted here inasmuch as prior to its being analyzed (by Dalton), it was dried at a temperature of 100° C. The remaining four are composed as follows:

1. Five-fold hydrous simple carbonate
of magnesia, according to Fritsche, S
2. Magnesia alba, according to Berg-25-

mann,

3. Do.

4. Do.

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Mg

H

25.39

23.70

50.91

45.

30.

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do. according to Berzelius, 30-25
do. according to Fourcroy, 48.

The corresponding proportions of oxygen are

40.

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2

4

3. Mg1Ï3+8H.

2. (Mg) C+3, or (Mg) C. 4. 3(Mg) C+H. The existence of the second and fourth of these salts must, until established by more accurate experiments, remain a matter of uncertainty. The two compounds alone, the composition of which is ascertained with sufficient precision, are, (Mg)1 C+2¤, Mg1 C3+8a, the oxygen ratio whereof was,

SECOND SERIES, Vol. VI, No. 17.-Sept., 1848.

27

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18-46 C: 18·46 Mg: 17-4718-46 : 18-46 Mg: 18·46 H 21.99 C 14-66 Mg: 29-32.

21.99 C: 14-09 Mg: 29.64

4

The compound (Mg) C+2 was obtained from sulphate of magnesia by cold precipitation, by means of carbonate of potash with an excess of sulphate of magnesia; the compound Mg C3 +8, by the evaporation of a concentrated solution of carbonate of magnesia in water impregnated with carbonic acid at a temperature approaching the freezing point.

The principal inference to be deduced herefrom, is as follows. All the hydrated magnesian carbonates hitherto analyzed, when made amenable to polymeric isomorphism, may be ranged in two classes: 1. Semi-carbonate of hydro-magnesia; and 2. Fourfold hydrated three-fourths carbonate of (hydro-?) magnesia. The salts of the first group, generally speaking, are obtained by precipitation cold, and those of the second group by precipitation at an elevated temperature. In certain exceptional circumstances, in connection especially with a depression of temperature, the compounds of the first class are enabled to take up two atoms more, and those of the second group four more atoms (eight therefore in all) of water of crystallization.

ART. XVIII.-English Prefixes derived from the Greek; by Professor J. W. GIBBS.

MANY persons well acquainted with Greek fail to derive the full advantage of their knowledge, from not analyzing the Greek compounds found in the English language. To such, it is thought, the following investigation of the force of the Greek prefixes found in English may be of service. An intelligent use of words is certainly desirable for every educated person. Something also may be gained by scientific

arrangement.

These prefixes, it should be observed, although sometimes employed as prepositions with their complements, are originally and properly ad

verbs.

1. Amphi or amphis, Gr. dugl or augis, Æol. aunt, Sansc. api, Lat. ambi, amb, am, an, Old Germ. umpi, Germ. um, Anglo-Sax. ymbe, ymb, embe, emb; (connected with Sansc. ubhau, Gr. auqo, Lat. ambo, Goth. ba, both.)

(1.) on both sides; as, amphibrach, short on both sides, a poetic foot consisting of a short, a long, and a short; amphisbæna, moving either way foremost, the name of an animal so moving.

(2.) about, around; as, Gr. ¿uqidéw, to bind about. No example occurs in English.

2. An before vowels, or a before consonants, Gr. &v, &,

Sansc. an,

a, Lat. in, Germ. un, Eng. in and un; (connected with Gr. ävεv, Germ. ohne, both signifying without ;) denoting negation; as, anarchy, want of government; ambrosia, an imaginary food supposed to confer immortality; atom, an indivisible particle; abyss, a bottomless gulf. 3. Ana before consonants, or an before vowels, Gr. àvá, àv,: - Goth. ana, Germ. an, Anglo-Sax. and Eng. on; (connected with Gr. ¿vó, above.)

(1.) up, upward; as, anadromous, running up; anagoge, a leading of the mind upward.

(2.) over, about; as, anatreptic, overturning.

(3.) back, in a contrary direction; as, anacamptic, reflected, turned back.

(4.) back, to the original state; as, anatomy, the dissecting of an animal body into its constituent parts; analysis, the separation of a compound body into its constituent parts.

(5.) back, anew, again; as, anadiplosis, the use of the same word at the end of one clause and the beginning of another.

(6.) away; as, anachoret, a hermit, recluse.

4. Anti, Gr. avτl, Sansc. ati, Lat. ante, Goth. and and anda, Anglo-Sax. and and on, Germ. and, ant, ent, Eng. an in answer.

(1.) before, over against; as, Gr. ȧviineiua, to lie over against. No example occurs in English.

(2.) against, in opposition to; as, antipode, having the feet directly opposite; antipathy, opposite feeling. Also as a preposition with its complement; as, antiasthmatic, good against the asthma.

(3.) denoting correspondence; as, antitype, a figure corresponding to its pattern.

(4.) denoting alternation or reciprocity; as, antiphony, alternate or reciprocal singing; antistrophe, reciprocal conversion.

(5.) denoting exchange; as, antiptosis, the exchange of one case for another.

5. Apo, Gr. &лó,

Sansc. apa and ava, Lat. ab, Goth. af, Germ. ab, Anglo-Sax. and Eng. of.

(1.) from, off; as, apocope, the cutting off of the last letter or syllable of a word; apology, a speaking one's self off, a defense in words. (2.) away; as, apostrophe, a turning away.

(3.) out; as, apozem, a decoction; apologue, a saying out, a full narration.

(4.) down; as, apoplexy, a striking down.

(5.) denoting privation or negation; as, apocalypse, an uncovering,

revelation.

6. Cata, Gr. xaτá.

(1.) down, downwards; as, catarrh, a flowing down.

(2.) against, as a preposition with its complement; as, catabaptist, one who opposes baptism.

(3.) upside down; as, catastrophe, a turning upside down, overthrow.

(4.) denoting distribution, as a preposition with its complement; as, catamenia, monthly courses.

(5.) denoting perversion; as, catachresis, wrong use.

7. Dia, Gr. diú, Lat. dis; (connected with Gr. Sów, Lat. duo, Eng. two.)

(1.) in two, asunder, apart; as, diæresis, the resolution of a diphthong.

(2.) through; as, diameter, a line drawn through the center. (3.) thoroughly; as, diagnostic, distinguishing, characteristic. (4.) between, denoting reciprocity; as, dialogue, conversation be

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(1.) badly, with difficulty; as, dyspepsy, difficulty of digestion. (2.) denoting want or absence; as, dysorexy, want of appetite. 9. Ec before a consonant, or ex before a vowel, Gr. ¿x, ¿š, = Sansc. wahis, Lat. e, ex, Goth. út, Germ. aus, Eng. out.

(1.) out; as, eclogue, a selection; exanthema, an eruption.

(2.) away; as, eclipse, a failure.

10. En, Gr. v, Lat. in, Germ. in, Eng. in.

(1.) in, on; as, enclitic, leaning on.

(2.) among, as a preposition with its complement; as, endemic, among the people.

(3.) into; as, enallage, the change of one into another.

11. Epi, Gr. í, Sansc. abhi, Goth. bi, Germ. bei, Eng. by.

(1.) on, upon; as, epigram, an inscription. Also as a preposition with its complement; as, epitaph, an inscription on a sepulcher. (2.) to, unto; as, epistle, a writing sent to a person. (3.) in addition to; as, epilogue, a conclusion.

12. Eu, Gr. 8v, signifying well; as, euphony, agreeableness of sound. 13. Hama or a, Gr. dua, à, à, Sansc. sa, sam, Goth. sama.

(1.) together with, as a preposition with its complement; as, hamadryad, a wood nymph, feigned to live and die with its tree.

(2.) denoting sameness; as, adelphic, relating to brethren, or those from the same womb.

14. Hyper, Gr. nég, Sansc. upari, Lat. super, Goth. ufar, Germ. über, Eng. over.

(1.) over; as, hyperaspist, one who holds a shield over another. (2.) beyond, as a preposition with its complement; as, hyperborean, beyond the north.

(3.) denoting excess; as, hypercritic, an over rigid critic.

15. Hypo, Gr. úлó,: Sansc. upa, Lat. sub, Goth. uf.

(1.) under; as, hypothesis, a placing under, a supposition. Also as a preposition with its complement; as, hypogeum, the parts of a building under ground.

(2.) denoting deficiency; as, hyposulphurous, sulphurous, but having a less quantity of oxygen.

16. Is, Gr. els; (connected with Gr. év ;) signifying into; as, isagogic, introductory.

17. Meta, Gr. uerά,

Germ. mit; (connected with Sansc. madhya, Gr. uéoos, Lat. medius, Eng. middle.)

(1.) with; as, metalepsis, participation, the name of a figure of speech. (2.) after, of place or time, as a preposition with its complement; as, metacarpus, the part after or beyond the wrist; metachronism, a placing after the time.

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