to the general law of mutual influence, or tendency to equilibrium, and no other law is required to explain a change of size. For if there were in existence molecules of the same substance of different sizes (or in other words of different temperatures), there would be between them a tendency to equilibrium of size (or in common language, to a mean temperature); and thus this simple law of mutual influence will explain enlargement or contraction from variations of temperature; and the variations from a mean size, (a mean temperature,) arrived at when two different substances mutually act on one another, will be specific heat. The change of form and axes in molecules dependent on change of temperature, will be a consequence of change of size, according to some law yet unascertained.

This view, for which we are indebted to Mr. Whelpley, explains expansion without recourse to any intervening ether, or any imponderable agent, excepting the general force of attraction. Admitting these conclusions, it will follow that the forms deduced for molecules are their actual forms. We confidently believe it will soon be shown that this change of size and attendant changes in pulsating force, will sufficiently explain the physical effects of heat.*

A molecule according to these views, is spherical or spheroidal in form:

It exerts attraction in every direction; but this force on opposite parts is so related that one molecule attracts another by one side and repels it by the opposite (polarity):

In solidification (and sometimes before?) this attraction is axially polar; it admits of various degrees of axial concentration or diffusion, ($7 to 12,) of acceleration or retardation of action, (§ 15,) and of different degrees of radial force, which variations take place under the general law of mutual influence, or tendency to an equilibrium :

This attraction acts by pulsations; in solidification there are also compound pulses (undulations in intensity) consisting of a series of pulsations, and producing intermitted or seriate results (cleavage), which results are in all cases specific; the same pulsations (the optic nerve being sensible to them) produce the phenomena of light; they are also a means of producing chemical effects, especially when the pulsations exceed the rapidity of those for light, (the chemical rays being those beyond the violet ray or those which have been shown to be most rapid in vibration.) Thea and states of elements, or their passive and

The relations of heat and magnetism, are illustrated in a valuable article in this volume, by Prof. W. A. Norton, pp. and 207; and some following pages contain an interesting memoir on heat and light by Prof. Draper.

active states, the former changing to the latter under the action of light or the chemical rays,-will be different states induced by or through rapidity of pulsation, the rapid pulsation of molecular force (causing or constituting what we call chemical rays) inducing the same rapid action in molecules under their influence. Magnetism may be a condition in which the attractive force is in constant active onward transfer from particle to particle, and galvanism, a condition of similar transfer while an exciting cause is in operation.

In hemihedral prisms like those of tourmaline and topaz, the molecules must have been in this magnetic condition; for they exhibit polarity now when heated. In the right and left handed quartz and similar cases, where while forming one side of a molecular pole must have been differently affected from the opposite, we may believe that the pulsations were alternate along each axis, a, b, c; this would in fact be a spiral action and it would produce a right and left handed crystal, according as the spiral action was to the right or left.

We accord in many particulars here stated, with the general theory of molecules and molecular forces presented lately, with some important shades of difference, by Whelpley and Faraday, and based on that of Boscovitch.

The explanations offered show that very many of the phenomena of physical nature, may be understood on the idea that molecules are simply centres of attraction, the same attraction whose laws have been under consideration. But no property of cohesive attraction explains the limits and proportions observed in chemical combination. The ultimate nature of the molecule, or of the forces constituting them, (on which we forbear from remark in this place,) is our only appeal for an explanation of these chemical relations. When fully understood, it may appear that cohesive attraction with all its laws, is only a necessary result of this peculiar constitution. We need yet some facts to make it obvious how both classes of phenomena, those of aggregation and chemical combination, may be united in one continued series.

These theoretical suggestions on molecules are annexed to the preceding article, partly in elucidation of some facts before stated, but more especially to exhibit the bearing of the principles on different theories respecting the constitution of matter, and to show that what may seem to be discrepancies are not necessarily so.

There is a strange variance between the chemist and crystallographer. In treatises on chemistry, a theory of molecular forms is often presented as the truth in a chapter on crystals, the falsity of which is taken for granted in all the other parts of the work.

Nature with more consistency, points to a unity of truth. This truth cannot be reached through any one avenue of science. Chemistry teaches us the laws of combination governing molecules, and the attendant operations of molecular forces;-crystallography indicates to us the forms of molecules and the laws which govern in molecular aggregation;-the eye being sensible to the movement of molecular force, optics teaches us the rapidity, character, and physical effects of its pulsations:-and we add by our thermoscopic instruments, another sense, for ascertaining other laws of molecular action. When the mind is fully opened to all these several sources of light, their concentrated beams will enable us to see beyond doubt the minute molecule almost with the distinctness of visibility.

ART. XXXIV.-Results of the Examination of several Waters from Hartford, Conn.; by B. W. BULL.

THE different samples were taken from wells in the city of Hartford, Conn., May 28th, 1847. Their localities are as follows:No. 1 is from a well in the State House Yard, northwest corner. No. 2 is from the well of H. Seymour, 16 Main street. No. 3 is from a well on the grounds of the American Asylum. No. 4 is from Lane's Coffee House, North Main street. No. 5 is from the New England House, Front street.

The soil of Hartford is an alluvium of ferruginous clay, sloping toward the Connecticut River on the east, and overlying the red sandstone of the greater secondary of Connecticut. It is in fact derived entirely from the decomposition of the soft argillaceous and calcareous shales which characterize this part of that deposit. No. 3 is taken from the more elevated portion of the city. No.

1 is from the centre of the city, No. 5 from the eastern, and Nos. 4 and 2 from the northern and southern extremities respectively. The gases contained in the waters were not estimated, as the immediate object of the investigation was to ascertain the amount of solid matter; neither was their action upon lead observed, which would have been interesting if time had allowed, more particularly as the results obtained by Prof. B. Silliman, Jr., in his examination of waters for the city of Boston, show conclusively that the established opinion, that water containing sulphates in solution is without action upon lead, is not sustained by experience. A peculiarity in all of the waters with the exception of No. 1, is the excess of bases in combination with crenic acid and probably with organic matter in other modifications; an opinion derived from the fact that those portions from which the crenic acid had been separated by neutral acetate of copper, were upon conSECOND SERIES, Vol. IV, No. 12.-Nov., 1847.

49

centration and evaporation highly colored, the color disappearing upon ignition. This reaction was observed upon all the samples from which this acid was separated, but a deficiency of material precluded the quantitative estimation of it in all but No. 3, in which the amount was 2.6 grains in one gallon, a quantity not sufficient to saturate the excess of base. The large excess in most of the waters may appear to exceed the bounds of probability, but repeated and concurring experiments show the results to be correct. In the deficiency of knowledge in relation to the modifications in which organic matter exists in combination with bases in water, and the unsatisfactory methods which we possess for its determination, it was preferred to state the results as obtained without attempting to estimate the organic matter with which the excess of bases is supposed to be combined. Its presence was abundantly proved by the action of nitrate of silver in solution upon the specimen under examination.

There were no indications of phosphates, apocrenic acid, or of potassa. The soap test, as might be inferred from a glance at the table, indicates that they possess in an eminent degree the property of hardness, becoming, with the exception of No. 3, immediately and perfectly opaque upon the addition of the test to the waters contained in a wine glass, accompanied in Nos. 1 and 5 with the formation of a curdy precipitate occupying nearly half the bulk of the tested liquid. The order of succession, considering No. 3 the best, would be 3, 4, 2, 1, 5.

The following tables are the results of the analyses. Table I. shows the specific weights and the amount of solid contents as found by evaporation and ignition in conjunction with a known weight of pure anhydrous carbonate of soda, added to prevent loss by the decomposition of any chlorid of magnesium; the weight of No. 5 is that found by analysis. The weights and measures used were the French gramme and decimals, and the litre, but are reduced in the tables to standard Troy grains, and the U. S. gallon of 231 cubic inches, the weight of one gallon distilled water at 60° F. being taken as 58-328,886 grains.

Table II. gives the amount of the constituents as found by actual analysis, without reconstruction. The discrepancy between the footings of this and the next table, arises from the loss of oxygen which the bases undergo by the formation of haloid salts with chlorine.

Table III. In this table the results of the analyses are combined as they may be supposed to exist in the waters in their natural state. The method recommended by Fresenius has been followed in reconstructing them, and the conclusions, though liable to criticism from the well known impossibility of accurately reproducing their original combinations, are supposed not to vary essentially from reality.

Table IV. gives the relative proportion of water and solid contents in 1000 parts.

I would express my indebtedness to Prof. B. Silliman, Jr., for many valuable suggestions during the course of the accompanying analyses.

tents in one gallon, as found 41-479 32-157 19-334 37-102 by evaporation,

69.046

TABLE II.

Constituents of one gallon in grains, as found by actual analysis, without

Carbonate of soda equivalent to crenate of do., 1·517 6-462 6-892 13-756 15.507 Magnesia combined with crenic acid,

0.783

2.685

4-481 1-336

41.043 29-506 19-565 36-01258-450