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- - --- --strated the same fact for the stars, so that in the present, the new hypothesis, to be of any value, should present us state of our knowledge, independent of all hypotheses, with a state of things in which basic molecules: repre. the facts may be represented as follows, the symbol indi. senting bases of the so-called elements should give us cating the spectrum in which the lines are visible.
their lines, varying in intensity from one condition to Hottest stars (H+Ca+Mg
another, the conditions representing various compoundings.
Suppose A to contain B as an impurity and as an eleSun .. H+Ca+Mg+Na+ Fe Cooler Stars 51--- Mg+Na+Fe+ Bi + Hg
ment, what will be the difference in the spectroscopic result ?
A in both cases will have a spectrum of its own;
B as an impurity will add its lines according to the Coolest..
amount of impurity, as I have shown in previous papers.
Bas an element will add its lines according to the Following out these views, I some time since communi.
amount of dissociation, as I have also shown. cated a paper to the Society on the spectrum of calcium,
The difference in the phenomena, therefore, will be to which I shall refer more expressly in the sequel.
that, with gradually increasing temperature, the spectrum
of A will fade, if it be a compound body, as it will be Differentiation of the Phenomena to be Observed on the
increasingly dissociated, and it will not fade if it be a Two Hypotheses.
Again, on the hypothesis that A is a compound body, When the reductions of the observations made on
Tvations made on that is, one compounded of at least two similar or dis. metallic spectra, on the hypothesis that the elements
similar molecular groupings, then the longest lines at one were really elementary, had landed me in the state of
temperature will not be the longest at another, the whole ulter confusion to which I have already referred, I at once fabric of "impurity elimination," based upon the assumed made up my mind to try the other hypothesis, and there. I single molecular grouping, falls to pieces, and the origin fore at once sought for a critical differentiation of the of the basic lines is at once evident. phenomena on the two hypotheses.
This may be rendered clearer by some general conObviously the first thing to be done was to inquire siderations of another order. whether one hypothesis would explain these short line coincidences which remained after the reduction of all
General Cossiderations. the observations on the other. Calling for simplicity | Let us assume a series of surnaces A ... D, of which sake the short lines eommon to many spectra basic lines,' A is the hottest.
1 CHEMICAL News, Nature of the Elements.
January 3, 1879.
difference in the spe&ra of the bodies existing in the four WIGHEST furnaces would consist merely in the relative thicknesses
of the lines. The spearum of the substances as they exist in A would contain as many lines as would the spectrum of the substances as they exist in D; each line would in turn be basic in the whole series of furnaces instead of in one or two only.
Application of these General Considerations to Impurity
Elimination. Now let us suppose that in the last diagram (Fig. 2) the four furnaces represent the spectra of say, iron, broken up into different finenesses by successive stages of heat.
It is first of all abundantly clear that the relative thick. Enlil nesses of the iron lines observed will vary according as
the temperature resembles that of A, B, C, or D. The Let us further assume that in A there exists a substance positions in the spectra will be the same, but the intensia by itself competent to form a compound body ß by ties will vary ; this is the point. The longest lines, reunion with itselí or with something else when the tem- presented in the diagram by the thickest ones, will vary as perature is lowered.
we pass from one temperature to another. It is on this Then we may imagine a furnace B in which this com.ground that I have before stated that the whole fabric of pound body exists alone. The spe&rum of the compound impurity elimination must fall to pieces on such an hypoB would be the only one visible in B, as the spectrum of thesis. Let us suppose, for instance, that manganese is the assumed elementary body a would be the only one a compound of the form of iron represented in surnace B, visible in A.
with something else ; and suppose again that the photoA lower temperature furnace C will provide us with a graph of iron which I compare with manganese represents more compound substance y, and the same considerations the spectrum of the vapour at the temperature of the will hold good.
. furnace D. To eliminate the impurity of iron in man. Now if into the furnace A we throw some of this ganese, as I have eliminated it, we begin the search by doubly compounded body w we shall get at first an inte looking for the longest and strongest lines shown in the gration of the three spectra to which I have drawn atten. photograph of iron, in the photograph of manganese tion; the lines of qy will first be thickest, then those of taken under the same conditions. I do not find these B, and finally a would exist alone, and the spectrum would lines. I say, therefore, that there is no impurity of iron be reduced to one of the utmost simplicity.
in manganese, but although the longest iron lines are not This is not the only conclusion to be drawn from these there, some of the sainter basic ones are. This I hold to considerations. Although we have by hypothesis ß, y, be the explanation of the apparent confusion in which we and ở all higher, that is, more compound forms of a, are landed on the supposition that the elements are eleand although the strong lines in the diagram may repre- mentary. sent the true spectra of these substances in the furnaces B, C, and D respe&ively, yet, in consequence of incom- Application of these Considerations to Known Compounds. plete dissociation, the strong lines of ß will be seen in furnace C, and the strong lines of y will be seen in furnace
Now to apply this reasoning to the dissociation of a D. all as thin lines. Thus, although in C we have no line known compound body into its elements which is not represented in D, the intensities of the lines
A compound body, such as a salt of calcium, has as in C and D are entirely changed.
definite a spectrum as a simple one ; but while the specIn short, the line of a strong in A is basic in B, C, and
trum of the metal itself consists of lines, the number and D, the lines of ß strong in B are basic in C and D, and
thickness of some of which increase with increased quan
tity, the spectrum of the compound consists in the main so on. I have prepared another diagram which represents the
of channelled spaces and bands, which increase in like facts on the supposition that the furnace A, instead of
manner. having a temperature sufficient to dissociate ß, ), and a
In short, the molecules of a simple tody and a cominto a is far below that stage, although higher than B.
pound one are affected in the same manner by quantity in
so far as their spectra are concerned ; in other words, Fig. 2.
both spectra have their long and short lines, the lines in
The heat required to act upon such a compound as a salt of calcium so as to render its spectrum visible, dissociates the compound according to its volatility; the number of true metallic lines which thus appear is a measure of the quantity of the metal resulting from the dissociation, and as the metal lines increase in number, the compound bands thin out.
I have shown in previous papers how we have been led to the conclusion that binary compounds have spedra of their own, and how this idea has been established by con. siderations having for a basis the observations of the long and short lines.
It is absolutely similar observations and similar reason. * The figures between the hypothetical spectra point to the gradual:
ing which I have to bring forward in discussing the com. change as the srectrum is observed near the temperature of each of pound nature of the chemical elements themselves. the furnaces.
1 In a paper communicated to the Royal Society in 1874,
Analysis of Boiler Feed-Waters. January 3, 1879.? referring, aniong other matters, to the reversal of some It did not seem unnatural that the bases should increase lines in the solar spectrum, I remarked *:
their complexity by a process of continual multiplication, · “ It is obvious that greater attention will have to be the factor being 1, 2, or even 3, if conditions were availgiven to the precise character as well as to the position
able under which the temperature of their environment of each of the Fraunhofer lines, in the thickness of which
should decrease, as we imagined it to do from the furnace I have already observed several anomalies. I may refer
A down to furnace D. This would bring about a condi. more particularly at present to the two H lines 3933 and tion of molecular complexity in which the proportion of 3968 belonging to calcium, which are much thicker in all the molecular weight of a substance so produced in a photographs of the solar spectrum (I might have added
combination with another substance would go on conthat they were by far the thickest lines in the solar tinually increasing. spe&rum] than the largest calcium line of this region
Another method of increasing molecular complexity (4226'3), this latter being invariably thicker than the would be represented by the addition of molecules of H lines in all photographs of the calcium spectrum, and
different origins. Representing the first method by A+A, remaining, moreover, visible in the spectrum of substances we could represent the second by A+B. A variation of containing calcium in such small quantities as not to the last process would consist in a still further comshow any traces of the H lines.
plexity being brought about by the addition of another " How far this and similar variations between photo molecule of B, so that instead of (A + B)2 merely, we graphic records and the solar spectrum are due to causes
should have A+B2. incident to the photographic record itself, or to variations
Of these three processes the first one seemed that which in the intensities of the various molecular vibrations
s of the various molecular vibrations it was possible to attack under the best conditions, because under solar and terrestrial conditions, are questions which
the consideration of impurities was eliminated; the prior up to the present time I have been unable to discuss."
work has left no doubt upon the mind about such and
such lines being due to calcium, others to iron, and so An Objection Discussed.
forth. That is to say, they are visible in the spectra of I was careful at the very commencement of this paper these substances as a rule. The inquiry took this form to point out that the conclusions I have advanced are
Granting that these lines are special to such and such a based upon the analogies furnished by those bodies substance, does each become basic in turn as the temwhich, by common consent and beyond cavil and discus- perature is changed?. sion, are compound bodies. Indeed, had I not been careful I therefore began the search by reviewing the evidence to urge this point the remark might have been made that concerning calcium and seeing if hydrogen, iron, and the various changes in the spectra to which I shall draw
lithium behaved in the same way. attention are not the results of successive dissociations,
(To be continued) but are effects due to putting the same mass into different kinds of vibration or of producing the vibration in different ways. Thus the many high notes, both true and false, which can be produced out of a bell with or without its ANALYSIS OF BOILER FEED-WATERS. fundamental one, might have been put forward as analogous with those spectral lines which are produced
By W. F. K. STOCK. F.C.S., F.I.C. at different degrees of temperature with or without the line, due to each substance when vibrating visibly with Being frequently engaged in the analysis of boiler feed. the lowest temperature. To this argument, however, if waters, I have found, as a result of several years' exit were brought forward, the reply would be that it proves perience, that unless the person to whom a report is too much. If it demonstrates that the h h; drogen line submitted happens to be possessed of considerable in the sun is produced by the same molecular grouping of chemical knowledge, a statement giving an exhaustive hydrogen as that which gives us two green lines only analysis of a water residue is apt to be very much more when the weakest possible spark is taken in hydrogen puzzling than edisving, and, as a matter of fact, such an inclosed in a large glass globe, it also proves that calcium analysis is by no means necessary to the purpose of is identical with its salts. For we can get the spectrum selecting waters for boiler use. A much more simple of any of the salts alone without its common base, method of procedure has stood one in good stead in cald
we can get the green lines of hydrogen with several difficult cases, and is the one I always follow, of out the red one.
course with modifications to meet special requirements. I submit, therefore, that the argument founded on the Most of the readers of the CHEMICAL News will be overnotes of a sounding body, such as a bell, cannot be familiar with the characteristics of a good boiler water, urged by any one who believes in the existence of any but for the sake of making more complete the description compound bodies at all, because there is no spectroscopic of the mode of working, I may be allowed to point them break between acknowledged compounds and the sup- out as follow:posed elementary bodies. The spectroscopic differences 1. Freedom from any very appreciable quantity of between calcium itself at different temperatures is, as I
suspended mineral matter. shall show, as great as when we pass from known com
2. Absence of any trace of mineral acids or of acid pounds of calcium to calcium itself. There is a perfect
salts, or corrosive salts of any kind. continuity of phenomena from one end of the scale of
3. Absence of oily or fatty substances. temperature to the other.
4. A good boiler water should not contain more than
30 grains solids per gallon, and not more than half Inquiry into the Probable Arrangement of the Basic
of this should precipitate on boiling under pressure. Molecules.
| Some little consideration is here due to the statements As the results obtained from the above considerations
thus made. For example, the amount of suspended seemed to be so far satisfactory, inasmuch as they at once
mineral matter a boiler water may contain is, to a great furnished an explanation of the basic lines actually ob
extent, governed by the quantities of carbonates of lime served, the inquiry seemed worthy of being carried to a
and magnesia, and sulphate of lime it contains, and by further stage.
the manner in which the boiler is sed. If a water gave a The next point I considered was to obtain a clear
coherent deposit on boiling, I should feel bound to object mental view of the manner in which, on the principle of
to more than 2 or 3 grains of mineral matters per gallon evolution, various bases might now be formed, and then
in suspension, as tending to augment and harden such become basic themselves.
deposit; and, again, if a boiler were to be fed without • Phil. Trans., vol. clxiv., pait 2, p. 807.
subsidence or filmation, the same objection would hold
Analysis of Boiler Feed-Waters.
CHEMICAL NEWS, 1 January 3, 1979.
good on account of damage to pumping and feed appa: point clear to steam users. I have placed the limit of this ratus. With respect to mineral acids or corrosive salts figure in a water analysis for boiler purposes at 15 grains my opinion is that any such contamination ought to con. per gallon, which number is the result of observation demn a water utterly for boiler purposes, unless simple partly, and of inquiry amongst practical men using waters and effective means could be adopied for their neutralisa which were known to me. Any greater contents leads to tion.
more frequent blowing off and chipping than is the rule, The action of oils and fats has of late received con- and loss of time is the consequence. The evil becomes siderable attention in connection with boiler waters. For much worse if attention is withheld, and the ultimate some time the opinions respecting their influence were result is local overheating, unequal expansion and con: extremely various, but it is now pretty generally acknow traction, culminating either in sudden destruction of the ledged that their presence is of no possible good, and boiler, with its too-often attendant horrors, or the fabric may lead to very serious harm. The following case, becomes utterly leaky and unmanageable. The following which came under my own observation in March, 1876, is the method I have devised and adopted as embracing may be of interest in this connedion. A boiler at a large the whole of the foregoing, and as furnishing in a very ironworks in fthe Cleveland district was being fed with short time most reliable informat.on as to the character Tees water (a most excellent boiler water), which was of any given water generally:slightly heated on its way to the boiler, by the exhaust steam from the blowing engines, with which steam, how. 1. The suspended matter is determined by filtering ever, it never came into actual contact. It was observed
700 cc. of the water through tared papers. The that after the boiler had been at work for about two years,
residue is washed, dried at 110°C., and weighed, then the seed pipe supplying it with the warmed Tees water burnt and weighed again. The weight in centi. became leaky in places not far removed from a flanged grammes gives grains per gallon, and the difference joint, the perforations from which the water oozed being between first and second weighings gives crganic like very small pin-holes. The boiler was neighbour to suspended matter. another, having a cast-iron feed pfpe, in which no leak 2. The examination for free mineral acids consists in whatever existed. The faulty pipe was removed, and put testing the water, which must be rendered clear by into my hands for examination. I first of all paid atten
filtration, if necessary, with dilute cochineal tion to the feed water, and, finding no clue there, turned
tincture, and determining the acid so found with my attentions upon the pipe itself. I had some difficulty decinormal soda. If corrosive salts are suspected in detecting the exterior preparations, but where they they are best arrived at by the evaporation of a occurred the interior of the pipe was eaten away to such large volume of the water (700 to 1500 c.c.), and a an extent that a walnut would have laid in the holes.
trial of the action of the concentrated liquid upon These holes were filled with spongy masses of what a weighed strip of pure iron, which should be asterappeared to be serric oxide, but which upon analysis gave wards carefully washed with boiled distilled water, the following results :
then with strong alcohol, dried, and weighed. The Ferric oxide .. .. .. .. .. = 66'91 per cent
nature of the corrosive substance is, of course, Ferrous „
given in the report, with any other information the .. .. .. ..
23.69 Aluminic ,, .. .. .. .. .. = trace ,
analyst can supply regarding it. Calcic .. .. ...
3. Oily and fatty matters occasion a milky appearance Magnesic ,, .. .. ..
in water containing them, which disappears on Sulphur tricxide ..
treatment with a moderate quantity of ether. Oil Phosphoric pentoxide .. ..
or fat is determined by evaporating 350 c.c. on the Water .. ..
water-bath (with the addition of one or two drops . Organic matter .. .. ..
of dilute sulphuric acid) to about 70 c.c. The Insoluble i..., .. .. .. = 1'30 ,
residual acid liquid is cooled, digested with ether in
a stoppered tube about two centimetres diameter. 100ʻ57
The ethereal portion is decanted into a weighed
capsule, the acid liquid washed with more ether, The organic matter yielded oleic acid in quantity, on
which is added to that in the dish, and the mixed treatment with ether, and this, coupled with the presence of both ferric and ferrous oxides, and the comparative
ethereal solutions evaporated over the water-bath
and weighed; and this weight, reported along with ease with which wrought-iron filings are attacked by oleic
the weight of caustic soda needed to render the fat, acid in presence of water, when heated under pressure,
or oil, found harmless. It is only in condensed led me to adopt the following explanation of the corrosion.
waters that such substances are found as a rule ; if, The presence of the fatty matter must, under the circum
however, grease should occur in water, giving also stances, be attributed to accident; most probably this had
lime and magnesia salts, sufficient soda would be occurred during erection of plant. The first effect of the action of the fatty acid upon the metal was the produc
required for their removal also. tion of a ferrous salt, which was oxidised by the oxygen 4. The proportions of solids deposited on boiling under existing in solution in the water, the iron only being raised pressure and solids retaining solubility on boiling in the scale of oxidation, the fat acid being liberated, and under pressure, are found by taking an observation seizing upon another portion of metal, which was again
of the total solid matter the water contains, the oxidised, and so the action became local and continuous. evaporation of 70 c.c. in platinun, and drying at I do not believe the cast metal pipe would have suffered
100° C., is quite sufficiently accurate. It is then at all under such circumstances, because the graphite it necessary to boil 700 c.c. of the water for three contained would have protected it from corrosion, and hours in a flask connected by an india-rubber under my advice cast pipes were supplied to all the boilers stopper, with an inverted Liebig's condenser, well as a preventive measure. It is seldom, indeed, or never
fed with cold water. The boiled water is cooled that all the features I have pointed out would occur in
to temperature at which it was measured, and if any individual sample of water, and as a rule the most
the condenser has received proper attention, no the analyst has to do is to indicate what amount of scale. appreciable diminution of volume will have taken forming matter the sample contains; and when it is called place. The cooled water is run through a dry filter, to mind what terrible accidents have occurred, and are and 70 c.c. are evaporated at 100° C. as before. constantly happening, through the unadvised use of hard
The difference between the weights of the two waters, it becomes a matter of the utmost importance to
residues gives solids deposited on simply boiling. have some reliable and simple method of making this We have aow to add to this the calcium sulphaie