VOL. XXXII. No. 831.

ON THE VARIATIONS IN THE COMPOSITION
OF RIVER WATERS.*
By J. ALFRED WANKLYN.

I HAVE recently had an opportunity of making analyses of the water of the Nile, and have noticed a very interesting feature in that river.

The Nile is pre-eminently subject to flood, the rising of the Nile being, indeed, the chief event of the year in Egypt. Towards the end of May the Nile begins to rise, the increase in size being at first exceedingly gradual. In June the rise is just perceptible, and the river goes on increasing in volume until about the middle of September, in which month it usually attains its greatest size. Afterwards it sinks very gradually, and about Christmas it is low. From Christmas till towards the end of May the Nile remains pretty nearly stationary in size.

The cause of the rise of the river is said to be heavy rains in the months of April and May, the effect of this rainfall requiring the lapse of a considerable time in order to exert its full influence. Possibly, too, the melting of snow on mountains near the sources of the river may concur in flooding the river.

The height to which the Nile rises, as well as the exact period of the rise, varies from year to year, but it may be stated broadly that from the end of May until Christmas the Nile is more or less in flood, and from Christmas to the end of May the Nile is low. The following is a tabular statement of the composition of the water in different months:

comparative constancy of the hardness. On reflecting on ness of the chlorine and the constancy of the hardness become intelligible.

The water which swells the Nile in the latter half of the year is storm-water, being thick and muddy (as is well illustrated by the sample of Nile water exhibited in the Sanitary Exhibition). Storm-water sweeps over the surface of the country, without penetrating far below the surface, and we may very readily understand that such water, passing over a country long ago denuded of salt, should carry little or no salt into the Nile, which it dilutes, and so causes to contain only an exceedingly minute proportion of chlorine.

By about Christmas, the storm-water had ceased flowing into the Nile, which, during the spring half-year, must be fed with water which has passed deeper into the ground, and which has undergone concentration by evaporation, in addition to having washed extensive strata, from which, doubtless, it extracts chlorine. We can easily understand how the Nile should become more chlorinous as the spring advances, and how the chlorine should be at the maximum just at the beginning of flood-time.

* A Paper read at the Social Science Congress, Brighton.

carbonate of lime, we can understand that, from the slightThe hardness, on the other hand, being due mainly to ness of its solubility, the carbonate of lime, and consequently from the chlorine. the hardness, should be under totally different conditions

No doubt the débris carried mechanically down with the flood-water contains abundance of finely-divided carbonate of lime, so that the storm-water must always be saturated with carbonate of lime. When in flood, the Nile is, therefore, as hard as when it is not in flood, and the comparatively slight variation in hardness at different times will depend upon the varying amount of carbonic acid present

in the river.

Although in the Nile the phenomena to which I have just directed attention are exhibited in a very marked manner, yet such phenomena are not confined to the Nile. If the investigation were made, I have no doubt that other rivers the Danube, the Rhine, and even the Thames, for example-would be found to exhibit something of an analogous character, only in a far less degree; and when they are suddenly flooded these rivers should be less charged with chlorine than at other times. The importance of recognising the different causes to which Aluctuation of chlorine in drinking-water is due will be obvious when it is considered how great a stress is laid upon the presence of chlorine as an index to sewage contamination.

Reverting to the Nile, I may append some determinations of the amount of organic matter in it at different times, premising, however, that my analyses were of necessity made on water which had been kept for a considerable period of time. The results are the following:

The water of the Nile is, therefore, sometimes quite as much charged with organic matter as the Thames at Hampton Court, where the London Water Companies draw the water. But, like Thames water, it is, no doubt, amenable to wholesale filtration, and a Nile water company ought to deliver excellent water.

As will be observed on turning to the tabular statement above given, the water of the Nile is only about half as hard as the London Thames water. I have also to add that it is not charged to any serious extent with either magnesia or sulphates.

Statement of Results of Analyses of Potash Salts. THE information the Committee has received on this subject is limited to the opinions of a few chemists. Without endorsing the whole of the following observations, the Committee believes that the subjoined remarks will be read with interest and advantage.

Messrs. Wallace and Co. write:-"It is quite likely that the sulphuric acid exists in these kelp muriates not as sulphate of potash, but as the double salt,

3K2SO4 + Na2SO4,

discovered in kelp potash salts by Penny, of Glasgow; and if so, the large proportion of sulphates present in kelp muriates (usually from 4 to 6 per cent) would involve a slight alteration in the mode of stating the results, and would introduce sodium sulphate to a small extent. This view, however, even if proceeded upon in practice, would not interfere practically with the commercial value of the sulphates. There cannot be a doubt that the alkali present is carbonate of soda, both from the fact of these muriates not being deliquescent, and the impossibility of the existence of carbonate of potash and chloride of sodium together without mutual decomposition, otherwise carbonate of potash could be made by the simple process of mixing solutions of carbonate of soda and chloride of potassium."

Dr. Ulex, of Hamburg, writes:-"Potash, carbonate of potash, pearl-ash, generally contain sulphates (which require to be removed carefully by a chloride of barium solution before estimating the potassium). The whole of the potassium is estimated as chloride of platinum and potassium, and calculated to oxide of potassium. The sulphuric acid present is precipitated with chloride of barium as sulphate of baryta, the chlorine with a solution of silver as chloride of silver; the former calculated to sulphate of potash, the chlorine to chloride of potassium. The oxide of potassium equivalent to these two salts is subtracted from the total oxide of potassium, and the remainder calculated to carbonate of potash. Part of the sample is titrated with sulphuric acid, and noted as carbonate of potassium; subtract from this the carbonate of potash previously found, and calculate the difference to carbonate of soda."

Mr. Wm. Galbraith writes:-"Muriates,' which may be alkaline and contain sodium carbonate (and therefore will not contain calcium and magnesium soluble in water), I should state thus, combining the stronger acids and bases first:

Hydrogen

Calcium

Potassium
Iron

Magnesium
Sodium

Sulphate. Chloride.

CHEMICAL NEWS, Oct. 29, 1875.

"The free acid I state as sulphuric acid, as I cannot believe that it exists as hydrochloric acid, considering the heat of the furnace during the manufacture. Of course it is evident that the acidity will not be really due to 'free sulphuric acid,' but to an acid sulphate, probably often to be found in salt-cakes and potassium sulphates acid potassium sulphate, KHSO4. Lumps of chloride are of decided acid reaction. Of course carbonates should follow the same rules as the above."

66

Mr. M. J. Lansdell holds the following opinions:"I think, in this as in all other instances, it is a mistake to give detailed analyses showing any particular arrangement of acids and bases combined. I advocate a simple statement of the elements (or acids and bases) separately, and any combining of them I am inclined to look upon as padding" only (to use an expressive word), and as having weight only with the uninitiated. I do not object to a statement of any one (say a base) as being equal to a salt, not in the sense that that amount of that salt is present in that sample, but as a trade valuation of the base present according to a well-known or usual standard for its valuation. I find the practice of latter years, among our clients, is to ask only for certain determinations (in potash salts generally of potash only, or of potash and its equivalent amount of sulphate of potash or chloride of potassium), and not for detailed analyses, thus getting them done at a less fee. However, I should see no objection if the Committee thought fit to prescribe a mode of statement for detailed analyses which they found suited to the requirements of the trade, it being understood such analysis (quoted perhaps as the B. A. statement' or 'B. A. analysis ') was only a statement in a conventional form. Yet a statement of the elements (or acids and bases) determined with at most their amounts in equivalent proportions (each equivalent proportion = 1 of hydrogen) would give to each manufacturer an easy means of making all calculations useful to him as to value, or the capabilities of the articles for separation or manufacture thereof of any compound, and would not parade a lot of fictitious or suppositious information to impose upon or awe the ignorant. I incline to the belief that every analyst should have respect to the ends sought, and need not go beyond them. A trader only finding some constituent or constituents of value for his purpose, should be accommodated with such on paying properly for them, and should not be led to require as the thing' a lot of other information, involving greater trouble and higher fees, to the limitation of general reference to the chemist. sooner the public learns that chemists do not want to take advantage of them, but only to do what is of use to them, and that fees are not to be regulated by the number of items given (any more than an amount of money by the number of coins of various values it may be paid in, but also by the intrinsic value of each), the better I think it will be."

The

NEWS

The Committee has been re-appointed with a further grant of £20.

Communications should be addressed to the Hon. Secretary, Mr. A. H. Allen, 1, Surrey Street, Sheffield.

THE CONSTITUTION OF URIC ACID. By S. E. PHILLIPS.

IT is well for a young athlete to ever have before him a task which, by better skill or strength, he may hope some day to surmount; in my case, however, other considerations are paramount. I have, indeed, projected a type of murexide constitution which might cover its genesis from tartronyl, nitro-phenyl, cresyl, or naphthyl bodies, but have hesitated to publish that which does not seem to weli satisfy the end so much desiderated.

The amount of labour employed in the endeavour has been far more than I can promise in the future, with declining brain power, and I'must bequeath the difficulty to good friends, who may not be scientifically friendly.

As Strecker and Bayer have done so much in the matter, the hope is that, in spite of modern idiosyncrasies, they may go on to complete the history of alloxantin and the beautiful Tyrian dye, murexide.

Meanwhile, we offer the following section of that study having reference to the constitution of uric acid.

As the products of ordinary combustion are chiefly water and carbonic acid, so some of the products of human or animal combustion are notably urea, uric acid, and their analogues.

The heat- or life-giving process is, perhaps, a kind of nitrile reaction, by which ordinary materials are burnt or condensed to more ultimate products, as if the leading

type of animal function were -2HO, while the converse assimilation in the vegetable kingdom involved a building up of the ordinary materials under the dominion of +2HO. The thought is, that solar power is consumed in one phase and expended in the other.

That the urates, cyanurates, and others are not salts in any proper acceptation of that term, whether mono-, di-, or tri-basic, is a demonstration we must leave for the paper referred to, confining attention to the tabular genesis of uric acid and its analogues. (See below.)

In regard to the double lines of Nos. 1 and 2, the first thing to notice is the ready susceptibility of interchange between the upper and lower series-under hydride influences the two radicals, oxalyl and mesoxyl, readily pass into glyoxyl and tartronyl, and vice versa; and great has been the penetration to establish this much amid such complex materials, further darkened by imperfect types and confused nomenclature.

The folly of calling amides acids is well pourtrayed in this tabular series. Column 2 are all admittedly monureides. In the case of alloxan the nomenclature is exceptionally correct. We have alloxan and alloxanic acid-one the amide or urea, the other amide + 2HO, or the aminic acid; but oxalyl urea is called " parabanic acid," and the true acid form "oxaluric acid," and in a similar way malonyl urea is called "barbituric acid," &c. This also extends to column 3, where mycomelic acid, by another mode of genesis, is called "alloxanamide."

If the concretionary salts of lime and potash with uric acid be truly such, then it would follow that caffeine was a tribasic salt, and zinc amide would be a mono-, di-, or tribasic salt of zinc. All of which is equally absurd in sight of the fact that amides and ureas may have metal or other replacements of H. An urate of potash is similar

{

(C,H,O,)O+HỌ

2 Mesoxalic acid +

(C3O3)O+HO

Tartronic acid + urea

(C6H1O6)O+3HO

(3). { (CHO,O+HO

(4).

Malonic acid +

(C6H1O4)O+3HO

Glycollic acid

+ urea

4HO

==

2HO

=

+ urea 4HO

=unknown amide.

+ urea

(CO2)2Cу2H2N2 mycomelic acid.

(C4H104) Cy2H3N2

dehydric acid (?).

(CO)2Cy2H2N2

uric acid.

(C6H1O6) Cу2H3N2

glycoluril. (C4H3O4)Cу2H3N2

xanthine.

(C6H1O4)Cу2H3N2

(?)

{

(?)

(C4H3O2)O+HO

210

:

to a parabanate of silver, and the mistake will be fully evident on a fair comparison :A parabanate of potash would contain the elements of An oxalurate of potash

CO2(CO2)2HKN2.

CHEMICAL NEWS, Oct. 29, 1875.

One is an amide with 1K replacing III; the other is a true salt of potash.

It is important to appreciate the ideas conveyed by these types, and not less so to fully regard their temporary and à priori character. This may be seen in the effort to place guanine among these ultimates, where it is so intimately associated in the laboratory, otherwise we have given it a different notation, as associated with guanamine, C8H7N5; guanine, CO2C8H5N5. These are curious, as associated with other simpler bases, where C=6 replaces H, atom for atom, in ammonia varieties.

It will be perceived that the so-called pseudo-acid amides are (column 2) +urea-2HO, instead of 4HO, and this leads to a consideration of the generic character of that

reaction.

Applied to column 1, it is one of the simplest and widest character, but, although so well known, yet its true function is easier to notate than to describe in words :Hydrate + ammonia 2HO an amide. (C4H5)O+HO (C4Hs) H2N.

HH2N

The 2HO eliminated.

=

Applied to column 2, the notably curious thing to observe is, that the same tendency to elimination of 2HO still continues, and whether it be 2 or 4 HO will depend on the intensity of the conditions employed. What, then, is

the character of the reaction?

Experience teaches that two alternatives subsist. Either the radical will be degraded or nitrilised by loss of - HO, or a cyano re-arrangement will result. The first is well exemplified in the glucoside condensations of M. Schiff (see CHEMICAL NEWS, vol. xxviii., p. 116), thus:—

Esculetine aniline -2HO=(C18H5O6) PhHN (C18H5O6)O+HO+2PhH2N-4HO=(C18H3O4) Ph2H3N2 +3PhH2N-6HO=(C18H1O2) Ph3H5N3 The second may be expected in all ureide combinations, where the characteristic (CO)2 of urea changes, by loss of 2HO, to the production of cyanogen; and that this is the predominant feature of the case there can be but little doubt.

I do not wish to convey the idea that in all cases this tendency has been literally and exactly fulfilled, as repre; sented in the tabular series, but simply that a good ground is submitted for such à priori projections. In principle, the reaction is well known :

then have

acid

For the pseudo-2HO=(CO),(C6H2O4)H5N4=HION4 For the uric acid' -4HO=(CO)4(C6H1O2) H3N4=H8N4

It is true that such abortions of numerical proportion can be found in the types of M. Baeyer and others, but the presumption is strong that they have no place in the endless natural varieties of ammoniacal type.

It only remains to notice the vague uncertainties in connection with Nos. 3 and 7. M. Baeyer essays to prove "that hydantoin is really glycolyl urea."

Bromacetyl urea+H2O+H3N-H1NBr=

=CH (C1H3O) N2O. That this is an imperfect and roundabout way of getting "glycolyl urea" may be admitted, but that the product is, at the same time, "hydantoin," is quite another matter. In a study of the benzo-creatinine research of M. Griess, we have regarded hydantoin as—

+ H3N2HŐ ·

=

uramil.

Tartronyl urea (CO2) (C6H1O6) H3N2 (C6H1O6) CyH,N2 But how it is that two atoms of that amide break up, by oxidation, to the production of murexide, is the problem of problems which yet remains a reproach to chemistry.

ON THE MANUFACTURE OF WHITE
CAUSTIC SODA.*

By GEORGE E. DAVIS, F.C.S.
(Concluded from p. 200).

Section 5.-Finishing.

We have now in our settlers or in our pots liquor which has boiled to 280° F. and settled. This liquor is baled or run into other pots, and kept boiling until a temperature of 320° F. has been arrived at. From 290° F. to this temperature a scum forms upon the top of the pot which sometimes appears red or even black; this is often re

* From the Journal of the Society for the Promotion of Scientific Industry.

NEWS

A was from liquor boiled to 320° F., the liquors oxidised during causticisation, but no nitre added to pans.

B was from liquor boiling at the same temperature, but nitre added in the boat pans, and it may be worthy of remark that both samples were pressed and dried before analysis.

These salts are in some works put straight into the black-ash mixing; in others they are first washed with weak liquor; a different plan is followed by some, who put them into the strong pans, where the sulphite, sulphate,

and carbonate fall with the other salts, the chloride and

caustic being dissolved. No other precaution being

necessary for 60 per cent caustic, I will now turn my attention to the preparation of 70 per cent.

The liquors after boiling to 280° F. contain too many salts to always give 70 per cent with ease and certainty, so when this strength is required the best plan is to boil until the contents of the pot reach 320° F., and again allow it to settle. Chloride, carbonate, and sulphite now settle out, as may be seen in the following analysis:

with this the surface of the pot becomes covered with graphite. The cover is then placed on the pot and the fire urged until the workman declares it "up to heat;" the oxidation of the sulphides may then commence, and may be effected by two different methods; first, by the injection of air, and secondly, by the means of nitre.

In the first case air is blown into the caustic, which is now in the state of igneous fusion, until the sulphide of sodium is nearly oxidised to sulphate; a trace of sulphide is always left in at this stage, for if completely oxidised here, the action of the air would be sufficient to give a shade of green to the finished caustic, owing to the formation of a little sodium manganate. Many samples of commercial caustic soda will contain traces of sulphide, but there should be none in the best qualities.

Some manufacturers use a small excess of nitre, and destroy the green colour afterwards by the addition of sulphur or sodium hyposulphite, which latter is generally known in a caustic works as "crystal." In the case of oxidising with sodium nitrate, this salt is added cautiously in order to avoid excess, a trace of sulphide being also left

in as in the last method.

Whether the sulphide in this stage of its oxidation passes through the states of hyposulphite and sulphite into sulphate is difficult to say. Probably not, for a hyposulphite could not exist at this temperature, though there is just the possibility of its being split up at the instant of its formation into sulphate and sulphide. Sulphate is the ultimate product, associated, however, with minute quantities of either sulphite or sulphide.

If the oxidation takes place as indicated by Pauli, the caustic is in the state of igneous fusion, and contains water must be eliminated from his equation, for the no water in excess of that necessary to form the hydrate of soda; the reaction then would probably be

5Na2S+8NaNO3=5Na2SO4+4Na2O+8N.

After the oxidation has been nearly completed, a sample is withdrawn (preferably in a mould such as is used by pharmacists for casting the sticks of caustic potash in) and examined for its amount of total alkali. In this state it is a stick of coloured caustic, the intensity of the colour depending upon the mode of working, and appearing from a light brown to a deep red. If 60 per cent is being prepared the samples may be of the following composition:

Sodium hydrate ..

chloride..

41535

carbonate

B.

83.566

When making 70 per cent caustic by the plan of separating the salts in one operation, the liquor from the black-ash boat pans is boiled directly to 320° F., and allowed to settle from twelve to twenty-four hours, after which the supernatant liquor is baled off for finishing.

The boiling of the liquor is then continued, and when vne temperature of the liquor has reached 355° F. it will solidify well on cooling and will contain about 53 per cent of alkali. The temperature of the pot then rapidly rises until at about 400° F., when very little steam seems to be evolved, though the contents of the pot still contain nearly 20 per cent of water; at 460° F., a few degrees above or below, the caustic will contain as nearly as possible 60 per cent of alkali, at 470° F. it will contain about 61 per cent, and at 500° F. it will contain about 64 per cent.

About this time there is very little motion to the contents of the pot, and in a short time the heat has risen above the range of a mercurial thermometer. There is at this stage an evolution of some pungent matter due to the action of the caustic soda upon organic matters present in the solution, and which probably is of several kinds, and

sulphate..

silicate aluminate sulphide..

Insoluble

A.

82 193

A is a sample of the contents of a pot at this stage from a works where the solution of the bottoms was introduced into the operation pan.

B is from the same works when the bottoms were packed and sold, consequently not re-introduced into the process.

From the strength of the caustic as found by experiment the quantity of salt necessary to reduce it to 60 per cent is calculated, which is added, and the pot is again brought "up to heat," after which the fires may be allowed to burn out, and the pot settled. After allowing to stand for a time, which may vary from six to eighteen hours as the two extremes, but which is naturally about eight hours; the settling takes place as mentioned in Ralston's patent; "the oxide of iron is precipitated to the bottom of the vessel," and besides this the alumina separates itself completely from the sodium hydrate and falls to the bottom of the pot with the iron oxide as aluminate of soda, which is completely soluble in water.