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attitude is, to a large extent, due to the weight which he There are men of science employed at South Kensinghas wisely and bravely attached to the latter.

ton, it is true; but they, as we have said before, have no “ The proposal,” he says, “has not met with the

official voice in such matters as these. general acceptance which we anticipated for it. On Since

seems we may now hope that the land has the contrary, is strenuously opposed by what appears been saved for scientific purposes, it is much to be to be the whole body of opinion representing scientific desired that some representative of science in the House interests ; and, although it might be possible to provide

of Commons should move for a Committee on which the adequately for those interests and at the same time appropriate the site proposed to the British Art Gallery, I

Treasury and the Office of Works, the Science and Art cannot say that the discussions in that sense with which Department (though judging from recent events the lastwe have for some time been occupied have so far had named is too frequently ignored when questions directly any effect in diminishing opposition from those quarters." connected with its duties are under consideration), The opposition has, we may remark, not changed be

together with the Royal Society and the Professors of the cause the facts have not changed, and we do not think it

Royal College of Science, may be represented. would have been started if any modus vivendi had been

Mr. Goschen's answer on Monday to Dr. Farquharson's possible.

question as to what steps had been taken to provide for the And here we approach a side of the question which

building of the Science Museum, and for the extension of shows that as the world grows older, questions of the Royal College of Science so urgently required, shows science and art are not managed in this country any

us clearly that it will be some time before the teaching at better than they used to be, and that some radical change

South Kensington will have passed through its present dealing with A

camping-out stage.

to Tory government. It is easy to see that the adminis- “it has been impossible to take any steps towards betrative system and not party government is to blame.

ginning the erection of a Science Museum or the extenMr. Goschen, in his letter, states that Mr. Tate him

sion of the Royal College of Science until the question

connected with the British Art Gallery had been settled. self suggested the site on the science ground, and it I myself had visions of a scheme, independently of buildmay be that some friends of science have said or thought ing on the controversial corner, which I had thought hard things of Mr. Tate in consequence.

might have given ample satisfaction both for the present Mr. Tate replies :

and future to the scientific world, but the matter will

now have to be reconsidered.” “I did not suggest the site at the corner of the Imperial Institute Road, and was only aware of it when it In answer to another question Mr. Goschen admitted was pointed out to me as the plot offered by the Govern- that the scientific work at South Kensington is at present ment as a desirable site for the Gallery of British Art, cramped, and stated that, in conjunction with the Comand with that site I expressed myself satisfied.”

missioner of Works, he would endeavour to find some It must therefore be taken that it was the Govern- temporary buildings to meet the difficulty before the ment itself that offered the site. Did the Government final scheme is adopted. offer first and consider afterwards ? for Mr. Goschen Let us hope that, some time before another generation now admits that it “would not be wise to assign this has passed away, the “administration ” which has led to corner site to the Gallery of British Art.” Another point the present impasse may be ameliorated, and that useful can be best stated by again quoting from Mr. Goschen :- buildings on the site may prove to everybody the justice “When it [the scheme) was first mooted, the intention

of the views held by the men of science in this matter. was that works of British painters from the National and South Kensington Galleries should be transferred to

THE CORRESPONDENCE OF CHRISTIAN the new gallery. It has since been ascertained that the

HUYGENS. trustees of the National Gallery are not disposed to fall in with this intention, and that the Science and Art De- Euvres complètes de Christiaan Huygens. Publiées par partment is precluded by the terms of its various trusts la Société Hollandaise des Sciences.

Tome quafrom parting with many of its most important works.” trième, Correspondance 1662-63. (La Haye: Martinus The Science and Art Department is not more

Nijhoff, 1891.) cluded” now than it was when the land was offered to I E fourth volume of the Huygens correspondence Mr. Tate. The preclusion dates from 1857, and it covering the years 1662-63, is now before us. apparently was not known to those who, as it would now Although the interval, as regards fresh discoveries by seem, without consulting the Science and Art Department, the “Dutch Archimedes," was a comparatively barren were ready both to hand over pictures and land.

one, the 249 letters referable to it (to say nothing of We give these two instances as indications of the result supplementary documents) afford materials for much inof the present system of dealing administratively with struction, and some entertainment. It is much to learn such questions.

that the greatest astronomer of his time sought to keep We have already stated that the scientific world is in touch with Paris in respect to the cut and colour of under great obligations to Mr. Goschen ; but we must his clothes ; nor can we be indifferent as to the precise also point out that the President and Officers of the date of his beginning to wear a wig. On June 15, 1662, Royal Society, and the other men of science who at the age of thirty-four, he communicated to his brother memorialized Lord Salisbury and attended the deputa- | Constantine the distressing intelligence of his incipient tion, have rendered a service to science worthy of the 1 baldness; a remedy for which, in the shape of the best high position they hold.

| perruque to be had in Paris, was provided in the following

COR.

• pre

THE

October. A similar article of attire, despatched by him mathematician was to have himself bled, in order to get to the Hague for his elder brother's wear, figures in rid the sooner of a cold caught on the journey of six full several letters, and engaged many anxious thoughts ; days from Brussels ; and the operation, singularly enough, but a little plot concocted by the par nobile fratrum for produced the intended effect. His next desire was to place extracting the price-amounting to four and a half louis- himself au courant of the state of practical optics in the from the liberality of their father, the Secretary, appears French capital, and to compare his lenses with those to have been baffled. They were, indeed, often made to ground and polished by Auzout and D’Espagnet. The feel—though not with any unreasonable harshness—that handiwork of the latter excited his particular admiration; he who keeps the purse holds the reins; for the paternal but the secret of his methods was carefully guarded, and authority exercised in their family was of no shadowy Huygens records, with a perceptible shade of irritation, kind. The elder Constantine ordered his three sons- the vigilance of the Bordeaux alchemist over a case of middle-aged, in Dante's sense, though they were—from lenses which might, for the care bestowed in keeping realm to realm at his good pleasure, and was obeyed with them tucked under his arm, have been a box-full of out hesitation. And notwithstanding that his demands pistoles. He found, however, “Messieurs les Lunettiers” from Paris for optical toys-pocket-telescopes, magic- less advanced than he had expected in their grand lanterns, and the like-gave Christian considerable schemes for telescopes 80 and 100 feet in length. annoyance, he did not venture to refuse, or so much as He set out with his father for London on June 7, and both remonstrate against the fulfilment of paltry, troublesome, were present three days later at a meeting of the Royal and, to his sentiment, humiliating commissions. He, Society, where they were entertained with “occasional however, stooped instead to the scarcely laudable sub- observations," and "promiscuous discourses," relating to terfuge of begging his brother Louis, then in Paris, to petrifactions, the smutting of corn, the amelioration of abstract one of the three lenses of the lantern, and so flowers, and sundry other topics. Christian testified bring about at least a postponement of his father's ap- his usual courteous interest in the proceedings ; but expearance at the Louvre in the character of showman pressed, none the less, in one of his confidential letters to scientific “marionettes," no longer claiming even the to his brother Constantine, something of scorn for the distinction of novelty.

miscellaneous doings at Gresham College. And he felt Huygens spent the whole of 1662 in Holland, occupied himself, he said, no whit the wiser for his election as a mainly with experiments on the "weight and spring of Fellow of the Society on June 17, 1663. English festivithe air.” Pneumatic inquiries just then, largely through ties, however, he admitted to be splendid. “This is the Boyle's example, raised very general curiosity ; and pneu- true land of good cheer,” he wrote, after a succession of matic engines attracted much constructive ingenuity. dinners given by the Earls of Manchester, Albemarle, The mode of creating vacua had been recently arrived and Devonshire, all of which were outdone by the at; phenomena of an unforeseen kind thence ensued, brilliant hospitality at Roehampton of the Dowager and led to continual surprises; their investigation in- Countess of Devonshire. A Court ball evoked no special volved that of the qualities and functions of the air ; comment; and perhaps Huygens's most genuine interest upon which the learned, accordingly, promptly and in London was in his visits to Sir Peter Lely's studio. Both eagerly entered. Huygens among the number; yet with he and Constantine dabbled about that period in pastels, no result of the first order of importance. He fabricated and the recipe by which Lely's crayons were fabricated an improved air-pump; and observed by its means some was an object of eager desire to them. It was freely apparently anomalous effects, which occupied many of his imparted, and is here printed (p. 372). thoughts, and gave rise to an extensive correspondence, Huygens quitted London on October 1, and spent the both with French savants, and with Sir Robert Moray as remainder of the year in Paris. And since his movements the representative of the Royal Society of London. They were regulated, not by the claims of science, but by did not, however, prove to possess all the significance family arrangements, his letters thence referred to no which he was at first disposed to attach to them. Less critical problems of that age. They are accordingly than his customary success, also, about this time attended more “readable,” in the general sense, than might have his efforts to give to pendulum-clocks the perfection been expected from a geometer of his profundity ; those needed for the solution of the problem of longitudes. addressed to his brothers, which form the majority in the His coadjutor was the ingenious Alexander Bruce, a few present volume, being even playful and diverting. To

.

re

sult, took a pair of the carefully-adjusted timepieces on jively causeries, rather than formal epistles ; social jota trial voyage from the Hague to London in December tings, family intelligence, the first hints of his anticipated 1662. The sea was rough; the ship a small one, but triumphs, his unvarnished opinions of his contemporaries : with large capacities for rolling and pitching ; whereby a they alone were allowed to see that there was a keen edge test more searching than tolerable was applied to the to his wit. His erudite correspondents on occasions put novel mechanism. One clock, thus “furiously shaken,” him fairly out of patience ; yet to Louis Huygens alone lost the bob of its pendulum; the other stopped, and was it confided that he thought Chapelain intolerably their custodian, having succumbed to sea-sickness, could tedious, and Petit uncommonly dull. Constantine, on do next to nothing to remedy the damage. Evidently, the the other hand, was the recipient of his impressions purpose in view demanded some better invention, such as, touching the harpsichord performance of William Brereindeed, Robert Hooke had already hit off, but, after his ton, a distinguished member of the Royal Society. Its usual volatile fashion, had thrown, still incomplete, aside. effect upon a trained musician like Huygens can easily On arriving in Paris, April 3, 1663, the first care of our be gathered from the ominous facts that the player was self-taught, and executed fantasias chiefly remarkable ence, of what is best fitted for the purpose to which it is for their disregard of every known rule of composition. to be applied. This may or may not be the explanation, Touches of family affection here and there relieve the

but the interest of the study of such an animal as the

horse will be increasd tenfold by the conviction that there intellectual pre-occupation lending its prevalent stamp to

is some true and probably discoverable causation for all the Huygenian correspondence. One likes the great its modifications of structure, however far we may yet be man better for his questions about the walking and talk- from the true solution of the methods by which they have ing achievements of his little niece, Gertruid Doublet, been brought about.” than for having solved the problem of the centre of

Here natural selection is not so freely and fully acoscillation, or discovered the isochronism of the cycloid. cepted as many would wish. But the grounds of doubt The maiden's modest proficiency was not carried to a

are not indicated. On the other hand, use-inheritance high pitch. She died in 1665, at the age of four.

fares worse. It is not so much as hinted at. It is well in the way of astronomy, Huygens did nothing of known that there are, especially in America, biologists of much moment during this interval. Admonished by

standing who contend that differentiations of structure Boulliaud of its visibility, he made his first observation

are largely due to a Lamarckian factor in evolution ; and of Mira Ceti at the Hague, on August 15, 1662, when it they adduce specialization of tooth-structure and of limbwas nearly as bright as « Ceti (fifth magnitude). The next

structure as evidence of the inherited effect of mechanical account of the star is on September 15, three weeks at

strains and stresses. Now, in the horse specialization in least after a maximum ; and its declining state seemed to Boulliaud marked by the flaring and flashing of its light, and not a few biologists would, we think, have been glad

teeth and limbs has been carried far. The general public as if in truth a semi-extinct conflagration revealed itself

to learn the opinion of the Director of our National in his telescope. “C'est un spectacle,” he adds, “à faire

Museum as to the scientific value of such views in so far désespérer Aristote et ses disciples” (“Corr. de Huygens,”

as they apply to the subject of his "study." t. iv. p. 231). Occasionally, too, Huygens pointed out

On another point of very general interest Prof. Flower the sustained conformity of the Saturnian appearances to does, however, express an opinion. It has been suggested his theory of them. The logic of fulfilled prediction had, that the horse has been separately evolved in America indeed, by this time persuaded all but the few outstanders and in Europe through a parallel but not identical series · always averse to conviction by truth, that the hypo- of ancestral forms. The evidence for this hypothesis is thetical and the real systems were practically identical.

generally regarded in this country as insufficient, and it The two years embraced by the present section of this is now held that the horse was probably evolved on the grand work were exceedingly peaceable ones. The

Western Continent. This is the view adopted, with his gates of the Temple of Janus in the republic of letters accustomed caution, by the author of this book. remained fast shut as they slipped by. Scarcely a ripple of contention stirred. Everyone was in good humour,

“It is,” he says, " by no means impossible that America and carped at his rival's doings only sotto voce-a state

may have been the cradle of all the existing Equida, as

it seems to have been of such apparently typical Old of things peculiarly agreeable to our Batavian philo- World forms as rhinoceroses and camels, and that they sopher, who loved not to have his meditations broken in spread westward by means of the former free communiupon by the shrill outcries of wounded self-love. Could cation between the two continents in the neighbourhood it but have continued ! But that was not to be.

of Behring's Straits, and, having prevailed over the A. M. CLERKE.

allied forms they found in possession, totally disappeared from the country of their birth until reintroduced by the agency of man. This supposition, based upon the great

abundance and variety of the possible ancestral forms of THE HORSE.

the horse which have lately been discovered in America, The Horse : A Study in Natural History. By William may be at any time negatived by similar discoveries in

the Old World, the absence of which at the present time Henry Flower, C.B., F.R.S., &c. (London: Kegan cannot be taken as any evidence of their non-existence.” Paul, 1891.) F there be a fault in the admirable little volume which

The discovery in the Old World of ancestral PerissoIF

Prof. Flower has contributed to the “ Modern dactyles, in numbers at all comparable to those which Science " series, it is that the author too cautiously with have been found in America, would no doubt throw a holds his opinion on certain broad biological questions flood of light on difficult questions of evolution and disin which not only naturalists but the general reading tribution. If, as Madame Marie Pavlow has suggested, public are just now specially interested. Early in the

Sir Richard Owen's Hyracotherium is (perhaps) identical first chapter, for example, we read :

with Prof. Cope's Phenacodus, similar genera have existed

on either side of the Atlantic since early Eocene times. “In many organs, but especially in the limbs and teeth, we find the strongest evidence of two opposing scendants. Between the primitive Phenacodus and the

In both continents these early forms presumably left deprinciples striving against each other for the mastery in fashioning their form and structure. We find heredity, existing horse there are many intermediate forms, some or adherence to a general type derived from ancestors, of which seem to be generically identical in America and opposed by special modifications of or derivations from in Eurasia. Have there, then, been many successive that type, and the latter generally getting the victory, migrations from the West? Have there been counteralthough in the numerous rudimentary structures that remain there is significant evidence of ancestral conditions migrations from East to West? What have been the longpassed away. The various specializations, evidently relations between the indigenous descendants of Hyracoin adaptation to purpose, will be thought by many to be therium and the successively immigrant descendants of the result of the survival, in the severe struggle for exist- Phenacodus? These and other questions may possibly receive some sort of tentative answer through the re

OUR BOOK SHELF. searches of the palæontologists of the future. Prof. Flower is no doubt wise in not attempting to theorize on

A System of Sight-Singing from the Established Musical

Notation, based on the Principle of Tonic Relation. the subject; but this is the kind of question on which,

By Sedley Taylor, M.A. (London: Macmillan and in our experience, the "intelligent layman," whom the

Co., 1891.) editor of the “Modern Science " series has in view, most greedily seeks information. Details of structure, no

This book is divided into two parts: (I.) the tonic sol-fa matter how clearly and lucidly described, do not appeal notation, (11.) the staff notation. Part 1. differs from the to him. He says, in effect, to the distinguished man of writing music in the minor key. Mr. Taylor is an outscience : “My dear sir, from you I can take the details and-out tonicist, and therefore most strongly opposed to on trust; of them give me only sufficient to illustrate the so-called “ Lah mode” of the official system. It must your methods of research : what I really want is your consistency. For practical purposes, however, it is not

be allowed that Mr. Taylor's method has the merit of opinion on those broad general problems in which every so certain that the “ Lah mode" is a mistake. At any man of liberal culture, who follows the thought of his rate, the opinion of most tonic sol-faists appears to be in time, must take a keen interest.”

its favour, as being the best method, from a utilitarian Prof. Flower divides his book into four chapters, of point of view, of treating the minor mode. which the first deals with the horse's place in nature, and

Part II. is an application of the tonic system to the its ancestors and relations. The second chapter is devoted ordinary staff notation. Mr. Taylor suggests that the

line or space on which the tonic falls should be clearly to the horse and its nearest existing relations. This con

marked by a thick line, of varying colours for major and tains a short account of the tapirs and the rhinoceroses, minor keys. As long as there is little or no modulation as well as the existing members of the horse tribe. The in the music, there can be no objection to this, but when cuts with which it is illustrated are from photographs, modulation sets in, the appearance which the stave and are admirable. The last two chapters (iii. and iv.) assumes when these lines are inserted, becomes most deal with the structure of the horse, chiefly as bearing will suffice to show this.

puzzling. Two examples taken at random from the book

In Ex. 142 the Do-line changes upon its mode of life, its evolution, and its relation to

6 times in the space of 9 bars of 2-4 time. Ex. 147, in 4-4 other animal forms, the head and neck and the limbs time, has 5 changes in as many bars. being selected for detailed treatment.

It appears to us that these constant guides are calcuEspecially interesting are the paragraphs on the ergot, lated only to worry instead of directing the singer ; "the a roundish bare patch in the fetlock covered with rough staff” (to use Mr. Taylor's words) seems to us to point

graphic up-and-down-ness of the pitch-notation of the thickened epidermis. It is suggested, and the suggestion

out the way just as well without as with their assistance. is both valuable and interesting, that this represents The book is most clear, logical, and interesting through

out; and whether one agrees with the reforms proposed “the palmar or plantar pads of those animals which walk

in it or not, one cannot help feeling that the author, in his more or less on the palm and sole. Owing to the modi- endeavours to minimize the difficulties of vocal music, fied position of the horse's foot, standing only on the end of the last joint of the one toe, this part of the foot no

deserves the thanks of all musicians. longer comes to the ground, and yet the pad with its bare and thickened epidermic covering, greatly shrunken in

The Statesman's Year-book for the Year 1892. Edited dimensions and concealed among the long hair around,

by J. Scott Keltie. (London: Macmillan and Co., and now apparently useless in the economy of the animal,

1892.) remains as an eloquent testimony to the unity of the The“ Statesman's Year-book" is too well known, and horse's structure with that of other mammals, and its too highly appreciated, to need the commendation of reprobable descent from a more generalized form, for the viewers. It presents such great masses of important well-being of whose life this structure was necessary.” facts, and these are generally so accurate and so well

arranged, that the work has become indispensable to all Of the other callous patches, the so-called“ chestnuts," who desire to obtain the latest information on the various or “mallenders ” and “sallenders,” which occur on the subjects with which it deals. The changes for the year inner aspect in the fore-limb just above the “knee," and 1892 are described as “heavy and extensive," and all of in the hind-limb just below the “hock," Prof. Flower says

them, we need scarcely say, add to the usefulness of the

volume. The date of issue was somewhat later than that their signification and utility are complete puzzles. usual ; but it was well worth while to postpone publica

There are one or two misprints or inelegancies which tion, as the delay enabled the editor to include, among will probably be removed in a second edition. On p. 52 other valuable statistics, the results of the censuses of the we read: “The upper molars have a very characteristic leading countries of the world. This year the volume pattern, admirably adapted for bruising and crushing They relate respectively to the density of the population

has been enriched with four admirably executed maps. coarse vegetable substances, and which is clearly a modis of the globe on the basis of new censuses and estimates, fication of the pattern,” &c. Another redundant and the distribution of the British Empire over the globe, the before which occurs in the very awkward sentence on the partition of Africa, and the international frontiers on the top of p. 136. A somewhat quaint misprint occurs on Pamirs. These maps are most welcome, and will be of the top of p. 68, where the “various species of the

great service to all who may have occasion to refer to

them. American general called Merychippus and Protohippus" are spoken of. One can imagine how the printer's devil The Optical Lantern as an Aid in Teaching. By C. H. prided himself on his knowledge of American proclivi- Bothamley. (London: Hazell, Watson, and Viney, ties. They give the name "general” even to an ancient Limited, 1892.) fossil equine!

THOSE who wish to acquire a general knowledge with

C. LL. M. regard to the manipulation of an optical lantern, without

square inch,

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entering into the minor details, will find in this little book Temperatures in Model Boiler working up to 10 pounds pressure a most useful guide. The author has dealt with the subject rather curtly, but nevertheless in this space the

Water temperature

Steam temperature. 14 inches below upper

Thermometer in steam reader will find descriptions of various lanterns for different

Pressure, pounds per level.

space. methods of projection ; hints on the most suitable positions in which screens should be placed to be best viewed by audiences; the best kinds of burners for the lamps,

IOO

87 both oil and oxy-hydrogen, and the different adjustments

I 20

106 for producing good results. Many other useful hints are

140

126 given, accompanied by several woodcuts.

W.
158

145
174

164
188

179
200
212

205
LETTERS TO THE EDITOR.

215

212 226 222

55 [The Editor does not hold himself responsible for opinions ex

236
233

9! pressed by his correspondents. Neither can he undertake

239
235

10 to return, or to correspond with the writers of, rejected

239
235

IO manuscripts intended for this or any other part of NATURE.

239
235

1ο
No notice is taken of anonymous communications.]
Heat-Engines and Saline Solutions.

To avoid supersaturation of the steam it must be separated as

promptly as possible from the water, which it projects, more or MR. MACFARLANE GRAY (p. 414) appears to call in question less, into the steam space. It is this which renders it so immy assertion that in a vapour-engine a saline solution may take portant in practice to secure the most active circulation. Prothe place of a simple liquid when it is desired to replace water vision for this, whereby the water falls, whilst the steam rises, by a substance of less volatility, and that the advantage which can be made. Carnot proved to attend a high temperature can thus be attained Uniformity of temperature of the boiler contents is of the without encountering an unduly high pressure. He contends utmost importance ; and I was recently told by an able engineer, that “the saline mixture is not the ing substance. Carnot’s connected with the Midland Railway, that the unequal expanlaw refers to the working substance only, and not to anything sion of the boiler plates in locomotives on getting up steam was left in the boiler."

not only disastrous in its consequences, but impossible of prePerhaps the simplest way of meeting this objection is to point vention. Pursuing thermometric experiments, I found this not out that Maxwell's exposition of Carnot's engine (" Theory of to be the case, and on a first trial of suitable apparatus, I Heat,” chapter viii.) applies without the change of a single word, obtained the following result :whether the substance in the cylinder be water, mercury, or an Model Locomotive Boiler, showing Hottest Water at the Bottom aqueous solution of chloride of calcium. In each case there is a

under 212° (October 24, 1891). definite relation between pressure and temperature; and (so far as the substance is concerned), all that is necessary for the re

Upper level above fire... versible operation of the engine is that the various parts of the

Temperature below furnace

65 76

06 107 114 working substance should be in equilibrium with one another throughout.

Upper level above fire... 160 170 180, 190 196 198 199 204 209 Let us compare the behaviour of water in Carnot's engine

Temperature below furnace

122 134 156176 200 204 206 208 209 before and after the addition of chloride of calcium, supposing Upper level above fire... that the maximum and minimum pressures are the same in the Temperature below furnace two cases. The only effect of the addition is to raise both the superior and the inferior temperatures. The heat rejected at Lord Rayleigh's suggestion to use liquids of higher boilingthe inferior temperature may still be available for the convenient point than water, such as saline solutions, to get botter steam 'operation of an engine working with pure water. At the upper whereby to raise the upper limit of temperature in a steamlimit, all the heat is received at the highest point of tempera- engine, 'is not feasible. Increased elasticity of steam or increased ture—a state of things strongly contrasted with that which tension was long since shown by John Sharpe (" Annals of obtains when vapour rising from pure water is afterwards super. Philosophy,” vol. i. p. 459, 1813) to be due to a corresponding heated.

RAYLEIGH. increase in its density. He pointed out that at 212° the density

of steam was 150 times greater than at 32°, and at 252° it was

twice as great as at 212°. Increasing the density of the liquid Superheated Steam.

does not help us, but liquids of lower boiling-point yield vapours LORD RAYLEIGH louches on a most important question of higher density than steam ai equivalent temperatures. An. (February 18, p. 375), which merits the attention of all inter- hydrous ammonia vapour exerts a pressure of 4 atmospheres at ested in the economy of prime movers. Few have troubled 32°, and its density is about 0-2, whereas at 120° F. the pressure themselves with determinations of temperatures and pressures

is in round figures 285 pounds on the square inch, and its density within a steam generator. Ebullition means work, and the per

0.850. formance of work involves cooling ; hence the temperature of Properties of Saturated Steam as compared with Saturated steam in the steam space of any boiler is lower by several

(Anhydrous) Ammonia Vapour. degrees than the temperature of the steaming water. I have failed to find any record of this important truth, and shall be

Steam

Anhydrous ammonia. glad to know if my observations have been anticipated.

Prof. Cotterill, in his work on the steam engine (p. 33), referring to the process of formation of steam under rising pressure

Pounds per

Weight of
Pounds per

Weight of
Tem-

Temin a closed vessel, says :—“The mixture of steam and water

square inch

square inch,

vapour in perature pounds per

above the

perature must be supposed so treated that the temperature is sensibly

pounds per in F.

in F.
atmosphere.
cubic foot. atmosphere.

cubic foot. uniform. If the experiment were tried without proper precau. tions, the steam would probably be found to be of higher temperature than the water—that is, it would be superheated.” So 15

'07344 14.744

“ 1060 far as my observations go, this is impossible, and the steam is 30 273.9 *10790

*1639 never superheated by compression in a closed vessel, in contact 60

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212

212

210 212

steam in

above the

249.8

20

32
57.607

3072 '17493

2428 with water.

*30503 113

70 In a small experimental boiler the records of temperature 165

40053 1647 indicated as follows :

I 20

349.8
372:8

4096
*5587

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