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Loss of Nitre in the Vitriol Manufacture. {

May 30, 1879. gases, extend to the opposite side of the tube. Hittorf | very great, but in my opinion it is only possible to arrive has made known in what manner a magnet acts upon the at just conclusions by a long series of such tests. The rays of cathodic light. If the results which he has esta- arrangement of these results weekly was as follows :blished are applied to the movements of the rays of nega- Week ending ..

187 tive light, there follow, as necessary consequences, all the

pyrites used. movements which are observed in the green light under

nitre the influence of the magnet. The form of the luminous surface is quite independent of the form of the side touched

arg. oxygen in exit gases. by a conductor. It can be directly shown with gas

grains NaNO3 per cubic foot. densities somewhat greater than correspond to the pro

vol. per cent NaNŐz in acid used. duction of the green light that the spot touched by the

calculated as NaNO3 on 100H2SO4. conductor emits a cathodic light. Over the spot in ques. tion are seen spheroidal tults of blue light. The luminous

NaNO, lost. Tons. Per cent. On 100 Sulphur. green surface is merely the basis of these blue rays. The In acid used

0'228 5'36 Oʻ170 author has shown that the positive and negative light can

exit gases :
0:783 18:36

0-582 perfeâly interpenetrate each other for spaces of any As unaccounted for 36247 76:28 2'418 length. The intensity of the green light emitted from a point of

Total
4'258 100'00

3:170 the side of the tube, if the intensity of the exciting radiation is constant, decreases with the continuance of the The figures obtained are embodied in the following table, excitement. This decrease is the greater the stronger the and represent the results of seven series of large chamintensity of the exciting rays and the original brightness bers, all worked with Gay-Lussac towers, and all but one of the luminous point.

with Glover towers, the one exception denitrating its acii “ If between the cathode and the green luminous side by hot water in a long tunnel. (See Table on next page.) uf the tube there is introduced a solid body, its shadow is It will be seen that the unaccounted for loss has never thrown upon the side, since it excludes such rays of the been under 50 per cent of the nitre used, and in one case cathode as impinge upon it from reaching the side. If the has reached 90 per cent, which is not explained by the solid body after some time is removed, the shadow dis. percentage of nitre used on sulphur, as we haveappears, but an image of the body remains, distinguished Week No. 13, 52:6 per cent of nitre 2.683 on sulphur. from the surrounding luminous surface by its greater

No. 23, 90'43

= 3 831 brightness, and exactly reproducing the shape of the former The total nitre used beingshadow."

Week No. 13, 5'10

No. 23, 4'236.

It would seem that the unaccounted for loss is inti. LOSS OF NITRE IN THE VITRIOL

mately connected with the working of the chambers, as MANUFACTURE.

in most cases it is found that where the percentage of By JAMES MACTEAR.

nitre used on sulphur is high, so also is the loss of nitre

unaccounted for calculated on sulphur. The letters which have been published in recent issues of

As yet no one seems to have hit the blot-Where does the CHEMICAL News have thrown considerable light on

the loss take place, and under what conditions ? Did we the above subject, but much still remains uncertain.

It know this we should be able to manufacture our acid at a seems to me that it is the duty of those who have studied much reduced cost, were we able to avoid this unaccounted this subject to make public whatever facts they may have for loss, which is at least 2 to 3 per cent on the sulphur. ascertained, so that sound conclusions may ultimately be

The directions in which I have looked for a solution of drawn from a careful comparison and consideration of the problem arethese facts. With this view I beg indulgence and space A. Decomposition of the nitrous gases in conta& with for some details of the work I myself have done in hot kiln gas before entering the Glover towers or this direction, and trust it may also induce others to pub

chambers. lish the result of their researches.

B. In their passage through the Glover tower. Shortly speaking, the losses in the case of good plant C. In their passage through the series of condensing might be stated as occurring in two ways :

apparatus generally known as vitriol chanı bers. 1. As lost by escaping with the exit gases into the at. Hitherto my results have been much more of a negative mosphere.

character than otherwise ; but a record of failures is of 2. As lost in the acid in the chambers for use (which great use, and often leads to a right way out of a difii

may or may not have passed through Glovers). culty. If, however, the amount of nitrous compounds in the

I made a number of experiments on a series of vitriol escaping gases capable of absorption by caustic soda, chambers which had no Glover tower, and where during and the amount of nitrous compounds in the acid used, be the continuance of the experiments all the nitre was potted estimated, it will be found that these two sources of loss in a large pot placed at the end of the row of kilns, all are very far from accounting for the amount used.

the sulphurous gas passing over it. In my researches the estimation of the nitrous com

The data used in calculating out these experiments in pounds in the escaping gases was made by taking average No. 6 series of chambers were – samples over twenty-four hours, the aspiration being at a No. of experiment

hours. constant rate (a very necessary precaution); and the de.

tons pyrites

sulphur. termining the nitrogen present in the absorbing solution

lbs. NaNO3

per cent on sulphur. by means of the zinc and iron distillation with caustic soda

per cent oxygen in exit gas from Gay-Lussac. process, which I showed in a paper read before the New

grains NaNO3 per cubic foot in inlet gas to Gay. castle-on-Tyne Chemical Society, January 24th, 1878-—

Lussac. gives most accurate results when properly carried out.

cubic feet of exit gas calculated from oxygen. These daily average samples were checked by an ave

grains NaNO3 per cubic foot calculated. rage for the week, and only in very rare cases was there an appreciable difference from the average of the daily

un'accounted for or loss.'

actually found.

= per cent of NaNO3 charged = per cent on The amount of work involved in these experiments is

sulphur.

tests.

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On 100 S.

On 100 S.

100 100

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Tons. P.ct.
Tons. P.ct.

Tons. P. ct.
100 S. Tons. Pict.

100 S. 0'117 0:613 6:36 0'350 3448 35.80 14960 4'572 57.84 3.180 9:633 100 5.500 Oʻ194 1'052 11:30 0:616 3.136 33'70 1.840 5'089 54'70 3.000 9'304 100 5460 O'102 0-565 5:46 0*327 2*353 22'70 1'362 7430 71.84 4'311 10'348 100 6'000 Oʻ192 1'034 8.61 0.555 3.865 32*20 2.081 7'113 59*20 3.824 12'012 100 6:460 0'220 1:175 9'24 0.600 3.883 30'54 1.990 7657 60622 3.920 120715 100 6.510 0:156 0.880 7625 09450 4'320 35.63 2'210 6.922 57°12 3.560 12'122 IOO 6220 0'145 0-552 5'55 0*320 3.025 30-40 14750 6-373 64'05 3.690 9.950 100 59760 0'110 0'033 0.55 0'030 0.872 14:40 0.700 5*135 85'05 4•120 6040 100 4.850 0*190 1'056 12.20 0*700 1.953 22.60 1.300 5*621 65'20 3.750 8.630 5*750 0'093 0·529 6'00 0*310 3.509 40 20 2.060 4:696 53.80 2.760 8.734 5*130 O'110 08573 7:00 0*340 2.752 33-30 1•610 4'940 59'70 2.890 8.265 100 4:840 0'075 0.463 6:40 0*300 2.743 37:80 10770 4'052 55.80 2:620 7.258 100 4.690 0'049 0*287 3:40 09173 3710 44'00 2.244 4'420 52.60 2:683 8.417

5'100 0'135 0'756 10.00 0460 2.800 37.00 1.680 4'019 53'00 2.420 74575

4560 0'061 0.357 5:30 0·216 2.682 39.50 1:616 36751 55'20 2 260 6.790

4'092 0.012 0.069 1'29 0.420 1'543 28.85 Oʻ937 3.736 69.86 2.271 5'348 100 3.250

nil nil nil nil 1912 34'00 1'185 34714 66.00 2'301 5:626 100 3:486

nil nil nil nil 1'269 23'03 0.830 4'248 76'97 2-952 5'510 3.835 0.058 0:315 673 0'258 1'212 25.87 0.877 3'158 67.40 2.255 4:685 3'390 0'043 0.270 803 0'224 0659 19:57 0:546 2.437 72.40 2.023 3:366 100 2-793 0'039 0'228 5:36 0'170 09783 18:36 0.582 3.247 76•28 2.418 4'258 3:170

nil ni nil nil o'915 17:30 0:654 4375 82.70 3•128 5'290 100 3782 0'0066 0'036 0:51 0'022 0:384 9:06 0 383 6.568 90°43 3 831 7'290 100 4:236 0'074 0.437 6.82 0 240 1'506 23.52 0.852 4460 69:66 2.576 6403 100 3.688 0*032 0'161 2:58 0'093 I'301 20'92 09753 48763 76-52 2.759 6:225 100 3.605 nil nil nil

nil o'936 14.80 0.533 5.385 85920 3'073 6°321 100 3.606 nil nil nil nil 1418 20:63 0°745 5'455 79'37 2:866 6.873 100 3:611

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The following are the resul:s obtained :

kilns where the heat was highest 5.63 parts. The differLoss of Nitre in No. 6 Chambers, working large pot (A).

ence, 0'23 part, is very small and is not more than the

error which might be expected in such experiments, so Ist expt., 24 hours, 31 per cent of nitre used. that in this case I do not think we have proof of a greater 43

loss of nitre by the decomposition of the nitre at a higher 3rd 53 68

temperature, at least not to the extent that might be 4th 43 68

expected. A&ual average of 71 days, 60.4 per cent of nitre used. On the other hand, there has been required to keep the The average NaNO3 used during this time was 9 per the case of

chambers in as nearly as possible the same condition, in cent on sulphur and 60-4 per cent of total, or 5'44 per cent on sulphur has disappeared.

Large pot ..

9'0 per cent of nitre During the same time the gases entering Gay-Lussac

Small

116 contained on an average 3.71 grains NaNO3 per cubic foot, while the amount in the exit gas was o 30 grain, which Aues or in the kilns that more nitre is used is one that is

The fact that when using small pots in the part of the shows an absorption of 92 per cent. The gases entering quite beyond doubt and well known to all experienced Gay-Lussac were aspirated at a regular continuous rate of vitriol manufacturers. It seems to me to depend soine0'5 cubic foot per hour. The pyrites was charged at the rate of 8 cwts. per hour, and the nitre charged varied from what on the fact that at the high temperatures the nitrous 30 to 40 lbs. per hour.

compounds are driven off much more rapidly, and sent The method of working was now changed, small pots instead of in an equally distributed manner; it is more

into the chambers, as it were, in “ whiffs ” or “gusts" being used for the decomposition of the nitre, and these difficult to keep the chambers in good condition, and the were placed actually on the burning mass of pyrites in

amount of nitre used is therefore increased. the kilns. The following are the results :

If we assume that the absorption in the Gay-Lussac be Loss of Nitre in No. 6 Chambers, working small pots (B). equal in both cases to, say, 95 per cent of the nitrous

Ist expt., 48 hours, 45'3 per cent of nitre used. compounds entering, then the two cases above detailed 2nd 48 55'4

would show:3rd 48 42:6

A. 9 o per cent nitre used – 5'44 lost=3.56 entering tower. 4th 24 537

B. 11.6

-5.63 , = 5.97 Adual average of 7 days 48:6

The loss in exit gases would then beAverage NaNO3 used during above time 11:6 on 100 sulphur, 48.6 per cent of which has disappeared, or

A. 0:178 per cent on sulphur.

B. O'298 5.63 per cent on sulphur.

The gases entering Gay-Lussac contained on And if we take the exit loss in “A” as 100, the loss in average 4.85 grains NaNO3, and the amount leaving was "B" would be 167, or the loss by the method of working 0'058 grain, showing an absorption of 98.8 per cent. as in “B” required 67 per cent more nitre than that in

It would appear, then, that as far as these experiments“ A,” which is sufficiently convincing as to the inadgo we have lost in the case where the nitre was decom- visability upon this system. posed in the large pot in the colder portion of the Aue The above experiments, although numerous and in5:44 parts of nitre for 100 of sulphur, and in the case teresting, are by no means complete, and more light is where the nitre was decomposed in the small pots in the greatly wanted.

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234

Deviation of Polarised Light by Solutions of Inverted Sugar. Cay sa, 1879 It is pretty clear that there is a very large loss between

ON THE INFLUENCE OF the Burners and the Gay-Lussac towers; the experiments VARIATIONS OF TEMPERATURE ON THE in No. 6 series of chambers show that the loss was not

DEVIATION OF POLARISED LIGHT very greatly increased by the greater heat at which the nitre was decomposed, and at which consequently the

BY SOLUTIONS OF INVERTED SUGAR.* nitrous compounds and sulphurous acid began to react

By P. CASAMAJOR. upon each other. We are thus shut up to admit a large

(Concluded from p. 214.) loss or reduction of nitrous compounds in the chambers themselves, or no doubt where Glover towers are in use, in the Glovers and chambers combined. So far as my The announcement that it was at 92° that d became results go there is no proof that the loss is greater where equal to 0, led me to think, that, possibly, the law that I Glover towers are in use; it is, in fact, more the other had deduced from Clerget's table was not correct. It is way, for while the loss where no Glover is used amounts true that the temperatures given by Clerget only extend to in

from 10° to 35o C., but, between these limits the law which Case A, 5'44 per cent NaNO3 on sulphur, governs the deviations of inverted sugar as affected by B, 5.63

temperature, as deduced from his table, is represented by the whole series of experiments extending

over more than

a right line. This I considered as an important fact, a year of weekly testings, the loss when Glovers are used because I do not remember a single instance in which a is not more than about 3'5 per cent on sulphur. My own law is expressed by a rigorous right line, between limits opinion is that the greater regularity with which the that are sufficiently distant, in which this right line is not nitrous compounds are supplied to the chambers has a continued throughout. Having, then, very serious doubts great deal to do with the question of loss; but this is a about the accuracy of Clerget's table, I started to discover point not yet worked out, so far as I am aware, by any one.

what the true law was. The varying statements that one hears made are so

For this purpose I prepared pure sugar, by taking the contradictory that it were well that those who have trust. best cut loaf sugar and soaking it in 95 per cent. alcohol worthy experiments should publish them, so that by a for several hours, taking the sugar oui, letting the pieces careful digest and comparison we might come to some

drain, and drying them by hot air. valid conclusion. As for myself, I may say that at

This sugar, tested before inversion, gave exa&ly 100 by present I am halting between two opinions, but I trust the saccharometer. The solution, after the direct test, that experiments now in progress may enable me to decide was inverted and tried again in the saccharometer at either for one or the other.

several degrees of temperature. After making a great Mr. Davis, in his letter in the Chemical News, many tests at various temperatures, I was forced to the vol. xxxix., p. 216, refers to the escape of nitric oxide and conclusion that not only is Clerget's table correct for teminvites chemists to state their views, after which he will peratures between 10° and 35° C., but that the law regive the experiments which he has made on the subject. presented by— As a chemist who has failed completely in obtaining

d= 44 reliable means of determining the amount (if any) of nitric oxide in exit gases, permit me to appeal to Mr. held good even beyond 88° C., at which temperature the Davis as to whether he should not give us these results deviation is equal to 0. at once. As one of the Alkali Ac Inspectors, Mr. Davis ought I think to give us any information which may have obtained, I took a large sheet of cross-section paper

To enable an observer to seize at a glance the results I enable us to keep down the escape of noxious vapours, to

divided very accurately into inches and tenths of an inch. say nothing of the economy of nitre.

On the line of the abscisses I took for every degree CentiÍ notice from the correspondence generally that the grade a space equal to two-tenths of an inch, and, on the amount of nitrous compounds present in the actual acid line of the ordinates, I took for every division on the negarun off for use is not well known. It varies a good deal, tive scale of the saccharometer, four-tenths of an inch. but the tests in the table show what it has been in my I then drew a right line, connecting the point representing own case, and the following gives details of a number of

- 44 of the saccharometer scale with the point representtests of the works of my firm at Newcastle :

ing 88° C. This right line represents the law expressed Per cent of by the formula

Nitre used. Week No. 1 0-250 vol. p.c. NaNO3 in acid 23'0

d=-44+ 0'270

28.2 0'205

23:5

Afterwards I plotted on this sheet 68 observations made 0-252

274 at temperatures varying from 14° to 32° C. The result of 0'190

22'5 this operation was that, out of 68 dots, 10 were entirely O'108

II:8 erratic, 18 were exactly on the line, and the remaining 0:167

2145

dots were so close that their distance from the line could O‘104

be explained by an error of of a division in the observa

138 tion of the saccharometer. In explanation of these results, 0*207

24'0 I may state that the dots which I have called erratic were O'168

22:4

due to observations made on turbid solutions, or while the St. Rollox, May 20, 1879.

temperature was flu&uating.. Observations made under such circumstances cannot be expected to be accurate

The other observations were made under conditions inExperiments on Alpine Dairy Farming.Dr. W. finitely more trying to the eyes than those under which Engling and Dr. v. Klenze.—The vaunted alpine milk ordinary saccharometric tests are made. When the temdiffers from other good milk merely by a high percentage disk of double quartz becomes distinctly elliptical, and,

perature fluctuates in the least during an observation, the of milk-sugar and by the aroma derived from certain cdoriferous plants. The influence of manured pastures

at times, the line of separation between the two quartz plates as compared with unmanured has not been satisfactorily swerves alternately to the right and to the left. determined, and the authors purpose renewing their ex- * Read before the American Chemical Society, Feb. 6th, 1879. periments.' Butter seems to remain free from rancidity American Chemical Society. I have not thought it necessary to have the longer the freer the air from ozone.Biedermann's it engraved, as the explanation given in the text makes the subjent Central-blatt.

sufficiently clear.

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CHEMICAL NEWS,} Deviation of Polarised Light by Solutions of Inverted Sugar. 235

To obtain the different temperatures required for these the tube was different from that of the water bath, and experiments, I had to alter a saccharometer so as to in that the difference between the two temperatures must terpose a water-bath between the two optical portions in depend on the rate of heating the water-bath, i.e., on the a manner similar to that adopted by Dr. Ricketts. At size of the flame. the bottom of this water-bath is an opening, communica- I have mentioned that a thermometer with a long bulb ting with the interior of a closed tube, three inches long, may be the cause of serious errors ; so may a thermometer projecting at a right angle. To the closed end of this tube whose movements are too sluggish. In the thermometer a Bunsen burner was applied when the water-bath was to be that I have used, the bulb was very short ; the mercury heated. In this water-bath I placed the tube containing column was very fine, so as to respond very quickly to slight the solution of inverted sugar. This tube is made of thin variations of temperature. These thermometers have brass, and is closed at each end hy a glass plate, held by 40°C. on a scale six inches inches long. One goes from o, a screw cap in the ordinary way. In the middle of this to 40°, the next from 30° to 70°, and the third from 60° to tube a portion was cut off, two inches long, and as wide 100°. Particular attention was paid in these experiments as the diameter of the tube. Over the opening thus to keeping the water-bath in continued agitation immediformed was soldered a projection, as shown in figures i ately before taking an optical observation, and while the and 2 at A. At first I used a tube with a cylindrical pro observation was being made. The thermometer in the jection, of the same diameter as the tube itself, for the in- brass tube was also kept moving backwards and forwards troduction of a thermometer to ascertain the temperature for some time before looking through the tube. Unless of the liquid in the tube, in the manner adopted for Cler- these things are done, there is no certainty that the tem. get's thick glass tube. I think that the plan represented petature observed is that of the liquid in the tube. in fig. I and fig. 2 is preferable, as it allows the operator Il, as I am convinced in this case, from the numerous to agitate the solution by moving the thermometer back experiments I have made, observations on solutions of inwards and forwards in the tube. A great advantage ob- verted sugar, taken at any temperature, are as reliable as tained by having a projection of this shape is that the those made at any other temperature, there can be no

FIG. I

A

FIG. 2

2

А liquid in the projection does not rise or fall perceptibly / utility in heating the solution by the interposition of a when the thermometer is taken in or out. If the vertical water-bath. Taking observations at the temperature at projection has a small section, whenever a thermometer which the deviation is equal to 0, merely saves the trouble is placed in it the liquid rises in this projection, and a of dividingportion may be high enough to stand above the level of ihe water bath. Under these circumstances, this portion

D-d by 144 of the liquid gets cooler than the portion in the horizontal tube, and, if the bulb of the thermometer is longer than and it is not certainly worth while to go out of our way the diameter of the horizontal tube, the temperature indi- for this purpose. The most convenient plan for making cated will be too low. Too much care cannot be taken in observations on solutions of inverted sugar is to follow observing these minutiæ, as otherwise accurate results the directions of Clerget, which are the following :cannot be obtained. Even with the greatest care, it is A sugar solution is placed in the ordinary way in the impossible to avoid errors in the observation of solutions saccharometer, and the saccharometric test, D, is noted whose temperature does not remain constant. In this down. To a portion of this solution, say 50 c.c., are added connection I may be allowed to express the opinion that 5 c.c. of concentrated hydrochloric acid. These are it was due to the want of a tube like the one represented mixed by shaking up the graduated flask, and the flask is in fig. I and fig. 2 that Dr. Ricketts was led to take 92° placed in a water-bath and heated to 68° C., taking about as the temperature at which d becomes equal to 0. I have 10 minutes in raising the temperature. This solution is repeatedly found at 92° that the deviation is on the afterwards immediately cooled to a temperature between positive side of the scale, ranging from 104 to 2, according 10° and 35° C. We then placed it in a thick glass tube, as the observation was more or less accurately made. In provided wiih a vertical tubulure for the insertion of a his experiments, Dr. Ricketts did not take the temperature thermometer to show the temperature of the liquid at the of the liquid in his tube, but that of his water-bath. As moment of observation. This tube is made 22 centimetres his tube was made of glass, about one-eighth of an inch long, instead of 20 centimetres, so as to compensare for thick, we must suppose that temperature of the liquid in the the addition of one-tenth of hydrochloric acid. If th

86

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D-d=144

904

864

100

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236
Composition of a Boiler Incrustation.

CHEMICAL News,

May 30, 1879. temperature, at the time of observation, is t, and the de. Designation Saccharometric Test Corrected by Glucose,

of Sugar. viation to the negative side is d, we take the algebraic

(before Inversion). Inversion. Copper Test, difference of the two readings, D-d, which is the arith

Raw
861

87 metical sum. To find the correct quantity of cane

85

Refined-B sugar C, from these observations, we must remember that

911

92 for 100 per cent. of sugar,

--C
83

83
Raw
77

80
904
91

got

3:57 therefore,

80

84

IT'5

84 с

(D-d) x 100 and C=

84

89
144-1
144 - 1

751

79

81 If we have Clerget's table, we may, instead of making this calculation, follow the practical directions at the head

90

90

4:30 of the table.

95

941 Refined

78 Instead of inverting by heating to 68° C., and then

78

8.2 81

82 cooling down rapidly, it is advised by some authors that

7 Raw

25 the solution be mantained at 70° for at least 15 minutes. I can say, after doing both things repeatedly, that, in the

91

91

25 87

88 second case, the solution is no better inverted than in the

5 gc

91 first. Some persons think it necessary to heat at 70° for

25 88

87 an hour. This I did not try, as I had found no advantage

Manilla
82

81 in heating 20 mimutes longer than Clerget directs.

7 25 84

82 For solutions that are to be heated above 68° for experi.

7.92 mental purposes, it is necessary to neutralise the hydro

831

81

75

Melado chloric acid by a base, as otherwise the solution becomes

735

74

7.5

Domestic 82 very red. For this purpose the preference should be given

811 85

86 to carbonate of soda, which gives the best results. I put enough of carbonate of soda to make the solution slightly

781

764 alkaline, and afterwards make it acid with a slight excess In the case in which the test before inversion is lower of acetic acid. In this condition the solution may very than when corrected after inversion, the presence of an conveniently be placed in a brass tube. For some reason excess of lævo-rotatory substance is indicated. When, on which I have not been able to discover, when the hydro- the contrary, the test, before inversion, is higher than chloric used in inversion is neutralised by magnesia, the after inversion, as in the case of the Manilla sugar, an indications of the saccharometer are always too low. excess of dextro-rotatory substance is indicated. If these

When Venteke's saccharometer is used for testing in. sugars are inverted, and the solutions of inverted sngar verted sugar we are obliged to operate on solutions of are tested in the saccharometer at 88° C., they would show greater dilution than the normal solution containing deviations on the positive side of the scale. This, how26.048 grs. of sugar for 100 ç.c., because the negative ever, does not enable us to decide to what particular side of the scale is very limited, reaching only to – 16 on dextro-rotatory substance the deviation is due. some instruments. Á solution holding 26.048 grs. of sugar in 100 c.c. is tested directly. Then 50 c.c. of this are transferred to the beaker ; the 50 c.c. Alask is washed out, and the wash water is added to contents of COMPOSITION OF A BOILER INCRUSTATION beaker, and also io c.c. of hydrochloric acid. After the

By ALFRED SMETHAM, F.C.S., A.I.C. solution has been inverted and saturated with carbonate of soda, if necessary, the whole is put in a 100 c.c. flask, and enough water is added so that the whole solution at On analysing a boiler incrustation which was lately sub15° C. shall occupy 100 c.c. The result of the test, after mitted to me for examination I found it, after drying at inversion, has then to be multiplied by 2.

100° C., to have the following somewhat unusual com: I will conclude by giving from my books a series, 28 position : consecutive tests of raw and refined sugars. In the

Oxide of iron..

24972 second column I give the direct test, before inversion ; in Oxide of lead

8:41 the third column, the correct test, as afforded by inver.

Oxide of zinc..

44'39 sion. In a fourth column I have given the copper test Lime

0'99 for glucose, when I happened to have it. These glucose

Magnesia

0'77 tests show that the substances which reduce the alkaline

Sulphuric acid

I'22 tartrate of copper are, for the most part, without action Carbonic acid

3:34 on polarised light.

Insoluble matter in aqua regia..

5.60 * Since this paper was read before tbe American Chemical Society

Water of combination, organic Dr. Behr has kindly called my attention to a paper of Dr. Tuchschmid

matter, and undetermined

10:56 in Scheibler's Zeitschrift for 1870, p. 649. After a series of elaborate experiments, Dr. Tuchschmid concluded that Clerget's table was very reliable. He investigated the law of this table between 40 and 41.8°C.

100'00 Instead of the formula given above, he found

Before committing myself to an opinion as to its cause, R corresponds to C, S to D-d. I wrote to my clients asking them for particulars of con144 16035 -0.50578 T;

struction of the boiler, and learnt in answer that it was This formula leads to 87.34 C. as the temperature at which the de. viation becomes o. The law of d= -44-16035 +0*50578 T is also re.

a " hot-water circulating boiler for domestic use," and, pr sented by a right line. As to the results given by this formula, as

further, that the boiler and cylinder were constructed of co.npared with the one I have given, they may be judged by the "galvanised” iron, and communicated the one with the ollowing:

other by means of leaden pipes. Degrees C. Tuchschmid. Clerget.

The explanation which I gave of the cause was briefly 139

this :-The town water, with which the boiler was fed, 25° 131747

1315 126 458

and which is soft to commence with, would, on boiling, 123.875 124

be rendered still softer, and by constantly circulating

R=100 S

10°

139 1

35

126 5

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