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afferent muscular nerves. A number of other papers of anatomical and physiological interest were also read by the following :-Prof. Dixon (Dublin), the development of the achondroplasic skeleton; Prof. Anderson (Galway) ; Dr. Dickey (Belfast), the cervical pleura; Dr. Johnston (Dublin), the intercostal nerves; Drs. Goodall and Earle (London), the structure of the pancreas in relation to its functions; Dr. Maclean (Liverpool), phosphatides in the light of modern research ; Prof. B. Moore (Liverpool), the chemistry of hæmolysis; Dr. S. Spicer, some points in the mechanics of respiration ; Prof. Thompson, the development of the fætal heart; Dr. Leonard Hill, F.R.S., the influence of inhalations of oxygen on the onset of muscular exhaustion ; Dr. Rutherford, some points in connection with the anatomy of the cranium of the fish; Dr. Waterston, some instruments used in anthropometry.

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actions obtainable by stimulation of the abdominal sympathetic are not associated with sensation. The distinct reflex contraction of the abdominal muscles resulting from stimulation of the abdominal sympathetic is another reaction which it is difficult to believe is not associated with sensation. The latter phenomenon has a two-fold interest. in the first place, it is the basis of a well-known clinical syimptom, the rigid belly wall, and, secondly, it represents a form of tonic contraction not directly inducible by artificial stimuli.

On examining critically Haller's, and to a less extent Lennander's paper, we are struck by the fact that the stimuli used are unnatural in character. It is not likely that the viscera are equally responsive to all forms of mechanical stimuli. Twisting, stretching, or squeezing the wall of the intestine from the outside may be ineffective, because the nerve endings in these organs are adjusted for stimuli of another kind. In the case of the bile duct and of the ureters a twist produces no vaso-motor effect, but distension by injection produces a well

marked rise of blood pressure.

The "referred visceral pain ” was discussed next. Dr. J. Mackenzie denies that a viscus is ever directly painful, the pain felt being essentially a “referred one." For example, in pleurisy the lungs and parietal pleura are insensitive. While agreeing with Lennander in the view that the subserous layer of the pleura is sensitive, Mackenzie holds that the pain of pleurisy is mainly a referred pain due to cramp of the muscles of the thoracic wall. Mackenzie gives the following theory as to the mechanism of the different forms of " referred pain." He holds that stimulation of afferent visceral nerves by some influence increases the excitability of afferent centres in the cord connected with corresponding areas of skin. The pain is consequently referred to these cutaneous areas, and is only indirectly the result of stimulation of deep visceral afferents.

Head gives a somewhat different explanation. Impressed by the fact that inflammation of spinal ganglia produces herpes zoster, he was led to believe that afferent visceral fibres in their passage through the same ganglia as certain afferent cutaneous

can affect the adjoining cells connected with the latter and thus produce “referred cutaneous pain." This view is opposed to Müller's law, and was finally given up by Head. He ultimately transferred the seat of the nervous mechanism from the ganglia to deeper centres in the cord. The segments of the cord connected with “referred pain do not correspond with the segments of the spinal axis as indicated by the ganglia. Head suggests that the “referred pain " areas correspond with the primitive phylogenetic segments of the cord. He leaves the mechanism of overflow unexplained. A remarkable fact is that the area of skin affected by referred pain is a mere patch or couple of patches, not a segment, but nevertheless more or less segmentally arranged.

The deep visceral afferents from the heart are not only those which have been most fully investigated experimentally, but also form an intermediate group between the pure visceral deep afferents and those of somatic or muscular origin. The chief afferent nerve of the heart is the depressor, and the receptive field for its stimulation is its nerve terminations in the wall of the aorta. The most adequate stimulus is distension of the walls of that vessel. The result of stimulation is a lowering of blood pressure due to a diminution of vascular tone.

The nature of this tonc, like that of voluntary muscles, is still obscure. It is doubtful whether stimulation of the depressor gives rise to pain directly. The areas of referred pain given by Mackenzie are not cranial, as we should expect, since the vagus is a cranial nerve, but mainly lie in the chest wall. Tender spots, however, are also found on the head.

Prof. Sherrington then gave a brief survey of deep nonvisceral or muscular afferents. Since the work on this subject is largely due to himself, and since he has elsewhere stated his views more fully, it would not serve any good purpose to try to epitomise this part of his paper.

The paper was followed by an interesting discussion, in which Prof. J. S. Macdonald, Dr. Graham Brown, and others took part. The discussion chiefly referred to the nature and functions of the terminations of the deep

nerves

RECENT IMPROVEMENTS IN THE INTERNILCOMBUSTION ENGINE.1

II. WE have already explained how important in the

economical development of the internal-combustion engine is an accurate and precise knowledge of the physical. properties of the working medium. The two chief features of which a knowledge is required are the calorific value of the explosive mixture and the relation between the specific heat and temperature of the ignited gases. The calorific value has been carefully ascertained for most of the gases commonly used, but the specific-heat relation is still a matter of unfortunate uncertainty. At the Leicester meeting of the British Association in 1907, under the sectional presidency of Prof. Silvanus P. Thompson, the desirability of clearing up the doubts that surrounded this subject was so keenly felt that an important committee was appointed for “ the investigation of gaseous explosions, with special reference to temperature,

An account of the findings of this committee was published in NATURE of June 24 last. From our present point of view the important result of the committee's work is expressed in the following extract from its report :-“ Recent researches on the properties of the gases at high temperatures have definitely shown that the assumption of constant specific heat is. erroneous, and have given sufficient information about the magnitude of the error to show that it is of material importance. The closer approximation to the real cycle which is made by taking account of the actual properties of the working fuid, though it leads to some complication of formulæ, gives compensating advantages of real practical value.' This bears out, also, a remark made by the late Prof. Zeuner 2 to the effect that any rate there must be dropped from the theory of the internal-combustion motors the former assumption of the constancy of the specific heats of the products of combustion."

A curve connecting the specific heat at constant volume (Cv) of the mixture of gases, formed by the explosion of one part of coal gas in nine parts of air, with temperature centigrade (6), which was considered to be accurate within 5 per cent., was included in the committee's report. A formula which fits this curve closely is

Co=0:172 +0.075

1000' and although the constant in the second term on the righthand side of this equation can only be looked upon as a first estimate, however carefully chosen, the equation does, probably, represent the high-water mark in our present-day knowledge, and from it can be deduced the limiting theoretical efficiency of engine cycles in which such a working medium is employed.

It is well known that on the basis of a constant specific heat the ideal efficiency (n) can be found from the following equation,

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where r is the ratio of compression and y is the ratio of the specific heats. This relation applies with equal truth

1 Continued from p. 172. 2 “Technical Thermodynamics," hy Prof. Zeuner.

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whether the cycle followed is (1) the constant-volume cycle, the real maximum temperatures were also 1600° C. and (2) the constant-pressure cycle, or (3) the constant-tempera- 1000° C. This, however, would be open to several objecture cycle, an important discovery attributed to Profs. tions. As an instance, take the case of an engine which Unwin and Callendar. The problem now arises to re- by improved design was made capable of giving for the calculate the thermal efficiency (n) for a working medium same misture and the same compression ratio a higher of which the specific heat is not constant. Most of the maximum temperature and pressure. Such an effect might important internal-combustion engines operate the be produced, let us say, by decreasing the ratio of coolconstant-volume cycle, and if we re-calculate the equation ing surface to volume through an alteration in the amount to suit this case, making the necessary approximations to of pocketing. This new engine, on the basis of comparisecure a workable result of sufficient accuracy, and using with an ideal cycle having an identical maximum the above linear law based on the British Association Com- temperature, would probably show little, if any, improvemittee's figures for specific heats, we find that the new ment in relative efficiency over the old engine. Such a efficiency equals

result would tend to defeat the purpose for which com

parisons with ideal cycles are made. It would seem IT2+ T.

the author that the better way would be to compare both

old and new engines with an ideal cycle having a maxiwhere T, is the maximum absolute temperature (centi

mum temperature corresponding to the known 'richness of grade) in the cycle, T, the suction temperature, whilst in the mixture, its calorific value, and the ratio of coinis the value obtained from the equation

pression.

A factor that has affected most advantageously the recent progress of the internal-combustion engine is the

great improvement that has taken place in engine using here the value of q corresponding to the absolute

indicators. The old moving lever design, although zero of temperature. The value of T, is practically in

thoroughly serviceable for most steam engines and for dependent of the compression, and in round figures suitable

many

slow-moving internal-combustion engines, has to this calculation may be written down as 400. The value

been found entirely untrustworthy with modern highof T, for a given richness of mixture will depend upon speed internal-combustion engines. A

form of the degree of compression before ignition, and can be

instrument has been devised in which the recording calculated therefrom.

In this way a
new expression for

lever is a beam of light, which, having no inertia, has the real thermal efficiency can be obtained in terms, not no time-lag. This vitally important improvement in the of Tą, but of r, and the following table shows a few com- indicators was due, in the first instance, to the prescience parative figures worked out in this way. The figures for

of Prof. Perry,' and in its later sta to the experimental the “air-standard efficiency are also given by way of skill of P'roís. Callendar and Hopkinson. The writer has comparison.

recently calculated out the case of an indicator of which Thermal Efficiency.

the free periodic time of oscillation was 1/300 sec., and

Real thermal Ratio of compression • Air standard"

efficiency

has shown that explosions occurring even in so short a (approximate figures)

time as 1/200 sec. could be adequately followed and re4 0:43

0:30

corded. We believe that this oscillation period represents IO 0.60

0:45

about the sensitiveness of one of the reflecting indicators Ratio, air/gas=9/1.

used by Prof. Hopkinson at Cambridge, and the calculaIt will be seen that in each case the real efficiency is about

tion serves to show how accurately the new instruments a quarter less than the “ air-standard ” efficiency.

can be made to follow extremely rapid explosions. This discrepancy sufficiently explains why those associated

It would be useless to base any deductions on the with the design and building of gas engines have expressed

records given by one of the old type of instruments their dissatisfaction with the “air standard” of efficiency.

in such a sharp explosion as this. Errors of as much 5 per cent.

known The adoption of the “ air standard " has led to the setting

have occurred up as an ideal, to be aimed at and striven after, of a

in the measurements of horse-power made by the old

instruments, On the other hand, it cannot be denied series of figures which it now appears are about one-third above the thermal efficiencies theoretically possible, and it

that the older type was a great deal easier to handle, and is not surprising that engine builders, who from their

that it could be used by comparatively untrained persons. practical work realised that there must be something

The new reflecting kind, despite its accuracy of measurewrong with the theory as then put forward, should have

ment to within i per cent. of the power, is rarely seen in workshops, and the

of objected. It is not too much to say that had the engine

indicated horse. builders to depend in the past solely on scientific guidance

power ” has been very commonly abandoned in favour of

the measurement of brake horse-power both in the as the mainspring of their investigations, there would

case of large and small engines. In the case of the have been far less progress made than has been effected by the system of trial and error. Even now the state of

numerous small high-speed petrol engines, the practice of knowledge as

actually measuring brake horse-power is often replaced by to gaseous specific heats is so uncertain that no accurate quantitative theory of the thermodynamics

the use of a rating formula giving a “ nominal" horse

power. of the internal-combustion engine can be laid down. The

It seems at first sight extraordinary that there writer has, however, endeavoured to show here and else

should be a reversion to the old unscientific “V.H.P.." where how the problem may be investigated symbolically,

but, despite their apparent similarity, the “N.H.P." of and so prepared for expression in numerical form as soon

the old days of the steam engine and boiler, and the as the thermal properties of the gases are actually known.

rating H.P." of the modern petrol engine, are really based

there Mr. Dugald Clerk, in his 1907 paper' before the Institu

very different considerations, and, as tion of Civil Engineers, made some estimates of real

appears to be

every likelihood that the latter will be efficiencies hased on theoretical maximum temperatures of

constantly revised with the aid of the best scientific advice 1600° C. and 1000° C., and his results are given below.

possible, there is little real foundation for any scientific

objection to it. The pioneer work done by Prof. Callendar Ideal efficiencies

in promoting this advance cannot be too gratefully acknow

ledged. Others have also worked at the problem since, and If maximum tem. If maximum tem.

a considerable output perature of cycle

” of rating formula has resulted.
On air standard
perature of cycle
1600° C.

D2.N
That in most common

use is H.P.= where D is
0:195
0*242

2-5 3 0286 0'293

0:356 cylinder diameter in inches and N is the number of 4 0*354 0:356 0-426 cylinders. This formula

put forward with the 5 0:384 0-394

0:475

authority of the Royal Automobile Club, and experi0-439 0'443 0:541 has shown that in the great majority of cases

he It was apparently contemplated that these figures might it gives wonderfully good results. be used in comparison with engine performances in which

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1 "The Steain Engine," by Prof. Perry, p. 117.

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two

forinulæ since brought forward give a more accurate The author has tested the capacity for erosion of several measurement. It is, of course,

not fitted for explosives, and has found these to vary considerably, but with racing motors, in which everything in design is all give similar results with varied charges. Thus the sacrificed to piston speed, high mean pressure, and a

erosion due to one three-quarter charge was less than sufficient endurance to last through a few races.

For an

that of a full charge, but two three-quarter charges gave engine having 4-inch cylinders the Royal Automobile Club more erosion than one full charge. Two half charges gave formula gives a rating of 25.6 horse-power, which is about less, but three half charges gave more, erosion than one the brake horse-power that a normal engine of this size full charge. These experiments controvert the statement would yield when driven a normal speed. Racing which has been made frequently that the erosion due to motors of this size have, however, given almost, if not four three-quarter charges, as also that due to sixteen quite, 100 horse-power, and even if it were possible to do half charges, are equivalent to the erosion due to one so it is a question whether it is worth while to search fuli charge. out a formula which would embrace such divergent prac- A paper on the trials and performances of the S.S. tice and conditions of operation. The Royal Automobile Otaki, by Engineer-Commander W. McK. Wisnom, R.N., Club formula corresponds to combining a piston speed of is of interest in view of this vessel being the first merchant 1000 feet per sec. with a mean pressure of 67.2 lb. per

vessel fitted with combination of reciprocating and square inch. Before it can be revised a complete series turbine machinery. The Otaki built by Messrs. of careful experiments on engines of sizes ranging from Denny, of Dumbarton, and delivered in November, 1908. 2 inches to 10 inches should be carried out.

She has since completed a voyage to New Zealand and In the succeeding article the writer proposes 10 discuss back, and is virtually a sister ship to the twin-screw details of the recent mechanical improvement of the vessels Orari and Opawa, fitted with reciprocating engines internal-combustion engine in relation to the theoretical and constructed by the same builders. All three vessels investigations already discussed.

belong to the New Zealand Shipping Company. H. E. WIMPERIS. The only important differences in the vessels consist in

an increase in length of the Otaki of 4 feet 6 inches to

make up for the loss in cargo capacity due to three shaft CONFERENCE OF ENGINEERS AND SHIP- tunnels instead of two, and also the modified design of BUILDERS AT GLASGOW.

the stern and stern post in the same ship. The boiler

installations in the three vessels are identical. The engines A JOINT summer meeting of the members of the of the Otaki consist of sets of ordinary triple

Institution of Engineers and Shipbuilders in Scot- expansion reciprocating engines driving wing propellers, land and of the North-east Coast Institution of Engineers and a low-pressure turbine drivin a central propeller. In and Shipbuilders was held in Glasgow on August 4, 5, and 6. It is of interest to note that, although a large

ordinary ahead working the reciprocating engines exhaust

into the turbine, and change valves are fitted so that the number of works and shipbuilding yards was thrown

reciprocating engines can also exhaust direct to the conopen to visitors, no works in which Admiralty work is densers. under construction were included. This arises from the

At the trials on the measured mile at Skelmorlie the firms concerned paying respect to the wishes of the

Orari attained a mean speed of 14.6 knots; the Otaki, Admiralty that as much secrecy as possible should be

under the same conditions, attained a mean speed of observed regarding the details and progress of Govern- more than 15 knots for a total water consumption per ment work. Wednesday and Thursday mornings were re- hour of 6 per cent. less than that of the Orari. The total served for the reading and discussion of papers, of which

water consumption per hour in the Otaki at 14.6 knots we give brief extracts. Sir Andrew Noble contributed some notes on the history

was 17 per cent. less than in the Orari at the same speed.

On the run from the Clyde to Liverpool, with the vessel of propellants. Perhaps the easiest way of showing the partly loaded, on November 21 and 22, 1908, at about striking difference between the old gunpowders and some half power, the coal consumption was about 1.387 lb. per of the modern propellants is to quote two tables given horse-power per hour for all purposes. Scotch coal was by the author. As both the units of heat and the quantity used, having a heating value of about 7500 centigrade of gas vary considerably, depending on the pressure under

units. which the propellant is exploded, the author has taken the transformation approximately at the pressures at which

As regards the performance of the Otaki on service,

the coal consumption on the voyage from Liverpool to the propellants are generally used in guns.

Teneriffe was 11 per cent. less than the mean for the Older Propellants.

sister vessels Orari and Opawa under similar conditions Pebble R.L.G.

Mining Spanish and at practically the same speed. For the round voyage, F.G.

powder powder at the same speed, the coal consumption of the Otaki is Volumes of gas

278
263 360

about Units of heat

per cent. less than that of her sister ships. The 738

767 Comparative energy 200,438 198,924 194 094 186,120 179,478

engines of the Otaki made a non-stop run from Teneriffe

to New Zealand, a distance of 11,669 miles as logged, Modern Propellants.

which is probably the longest continuous run vet made by Cordi'e, Jialian M.D. Norwe. Nitro. Norwe- marine turbine. The turbine worked perfectly satis

Mark I. ballistite cordite gian 167 cellulose gian 165 factorily throughout the whole round voyage.
Volume of gas

875 5
810'5 9135

934'o 99999 Units of heat

The New Zealand Shipping Company is to be con12460

935'5 Comparative energy 1,090,873 1,057,703 940,905 904,850 863,016 851,212 gratulated in allowing this experiment to be made, and It will be seen from the tables that the comparative information contained in the paper regarding the perform

also for its courtesy in rendering available the very full energies of the modern explosives are more than four

ances of their vessels. times as great as those of the older propellants.

As regards the serious question of erosion, in the case of very large guns it is important to remember that, PAPERS ON REPTILES AND FISHES. while the surface of the bore subject to the more violent A NEW species of leatherx; or leather-back, turtle from erosion increases approximately as the calibre or a little

Maryland is more, the charge of the propellant required to give to Palmer in No. 1669 of the Proceedings of the U.S. National similar projectiles the same maximum velocity increases Museum under the name of Psephophorus calvertensis, this as the cube of the calibre. Consequently, unless special | being the first representative of the genus, which was arrangements as to the projectile are made, or other means previously known from the Tertiaries of Europe and Egypt, adopted, the life of the largest guns before re-lining must hitherto recorded from American deposits. It is, however, be short when compared with that of smaller guns. pointed out that certain dermal armour from the ZeugloAttention should be given to the best method of reducing dont Limestone of North America, figured by Müller in his erosion when very large charges are used, either by lower- work on Zeuglodon, probably belongs to the same genus. ing the temperature of explosion or possibly by introducing In No. 1681 of the same publication Dr. L. Stejneger some cooling agent with the charge.

gives the name Mesopeltis longifrenis to a snake from

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Panama, which appears to have been previously un- of Fossil Mammalia in the British Museum '') endorsed, in described.

a somewhat modified manner, this opinion, regarding the The first part of the second volume of the Memoirs of Multituberculata as primitive diprotodonts presenting some the Indian Museum is devoted to the initial portion of a

very specialised features. In the course of his investigareport, by Dr. N. Annandale, on the fishes taken by the tion Mr. Gidley has been led to conclude that Bolodon of Bengal fisheries steamer Golden Crown; this section, which the English Purbeck is inseparable from Plagiaulax, while is illustrated with five plates, dealing with the skates, rays,

the American Chirox is identical with Prilodus. and sawfishes. In the group of sting-rays and butterfly

The dental formula of Ptilodus is i.}, 6.1, p.s, m. rays, new species of the genera Trygon and l'rogymnus The lower jaw is attached obliquely to the skull in such are described and named, while in the torpedo-rays, in

a manner that its condyle is raised above the line of the addition to a new species of Narcine, Dr. Annandale pro

cheek-teeth (thereby doing away with an objection raised poses the unclassical term Bengalichthys" for a ray

by Owen against the herbivorous nature of Plagiaulax), distinguished from Astrape by its thickened and Aeshy disc, and the greater portion of the large cutting lower prerudimentary pectoral fins, and degenerate eyes.

molar does not, in consequence, bite against the upper A second new genus of rays, Dactylobatus, has recently cheek-teeth, which extend considerably in advance of the been proposed by Messrs. B. A. Bean and A. C. Weed

Mr. Gidley's views, especially if the Triassic in No. 1682 of the Proceedings of the U.S. National Microlestes (a name which it has recently been proposed Museum for a species of which two examples were taken

to replace by Thomasia) belong to the same group as off South Carolina nearly a quarter of a century ago. Plagiaulax; will considerably modify opinion with regard The generic name refers to the presence of a finger-like to the origin and radiation of the diprotodonts. process jutting from the middle of each pectoral fin, which, together with the subcircular form of the disc, distinguishes this handsomely spotted species from the typical rays of the genus Raia.

PROBLEMS OF AVIATION. In No. 1677 of the publication last quoted Messrs. D. S: THE interim report of the Advisory Committee for AeroJordan and J. O. Snyder describe, under the name of nautics, which, in his recent speech in the House of Coregonus oregonius, a " white-fish" from the Commons, Mr. Haldane promised shortly, has now been McKenzie River, Oregon, where it is locally known as published (Cd. 4711). It will be remembered that the the “ chisel-mouth Jack.' It is an active, predaceous fish duty of the committee is to advise on questions submitted about 18 inches in length, which takes the fly readily. to it by the Government departments to which the work

To the June number of the Zoologist Mr. R. Elmhirst, of constructing and experimenting with aëroplanes and superintendent of the Marine Biological Station at Mill- dirigibles has been entrusted. This work necessitates, in port, communicates a note on whelks as cod-food. Cod, some cases, experimental research at the National Physical it is well known, feed chiefly on crustaceans, but two Laboratory. The committee is intended generally cases are on record where large numbers of whelks were advance the applications of the science of aëronautics by taken from the stomachs of these fishes. Now, although such means as may seem best. It has arranged already these molluscs, generally with the operculums cut off, are for a series of reports as to the present state of knowfrequently used as bait in cod-fishing, the number of ledge on the questions which will have to be considered. whelks with their operculums in the two instances men- These reports are to include papers on the following tioned indicates that these had not been taken on lines, but subjects :-Mr. A. Mallock, on general questions to be devoured in the course of natural feeding. The author studied; Dr. T. E. Stanton, on recent researches on the is of opinion that cod seize whelks when the foot is pro- forces on plane surfaces in a uniform current of air : Sir truded, and swallow this part alone, rejecting the shell G. Greenhill, on stability and on the screw propeller; Dr. and its contents by means of a vigorous shake.

W. N. Shaw, on wind structure, dealing especially with In the same issue Mr. L. E. Adams gives some addi- the phenomena of gusts, and on the variation of wind tional notes on the flying-fish problem, in the course of velocity with height; Mr. F. W. Lanchester, on petrol which it is suggested that the discrepancy between the motors for aëronautical purposes ; Dr. W. Rosenhain, on accounts of different observers with regard to the occur- light alloys; and the secretary (Mr. F. J. Selby), on existrence of wing-vibration may be due to the personal ing knowledge on the subject of the accumulation of equation ” in the matter of vision-power.

electrostatic charges on balloons, and the precautions to be adopted to avoid the dangers arising therefrom.

To make it possible to decide what work should be

undertaken first at the National Physical Laboratory, the PRIMITIVE DIPROTODONTS.

committee drew up a list of desirable experiments as AT last, it seems the true position of Plagiaulax, of follows :

the Dorsetshire Purbeck, described by Hugh Falconer in 1857, has been more or less definitely determined, and

I.-General Questions in Aërodynamics. this by means of its early Tertiary American relative

(1) Determination of the vertical and horizontal comPtilodus, of which remains, in a much more satisfactory ponents of the force on inclined planes in a horizontal condition than any hitherto known, have recently been dis- current of air, especially for small angles of inclination to covered in Montana. These are described by Mr. J. W.

the current. Gidley in No. 1689 (vol. xxxvi., pp. 611-26) of the U.S.

(2) Determination of surface friction on plates exposed National Museum Proceedings under the name of P.

to a current of air. gracilis. Of late years Plagiaulax and Ptilodus, together

(3) Centre of pressure for inclined planes. with a number of more or less nearly allied types, collec

(4) Distribution of pressure on inclined planes. tively forming the Multituberculata or Allotheria, have been

(5) Pressure components, distribution of pressure and tentatively associated with the Metatheria on account of a

centre of pressure for curved surfaces of various forms. presumed resemblance of their cheek-teeth to those of the

(6) Resistance to motion of bodies of different shapes ; platypus.. A study of the skull, pelvis, and limb-bones of long and short cylinders, &c. the American genus has, however, convinced Mr. G'a'ey

(7) Combinations of planes: effect on pressure comthat this is wrong, and that the Plagiaulacidæ (together ponents of various arrangements of two or more planes. with the other Multituberculata) are really marsupials. The unequal development of the fore and hind limbs, the

II.-Questions Especially Relating to Aëroplanes. characters of the incisors, the form of the palate, and the (8) Resistance components for aëroplane models. position of the cheek-teeth indicate, in his opinion, a close, (9) Resistance of struts and connections. al:hough not ancestral, relationship with the diprotodont (10) Resistance of different stabilising planes, both marsupials.

horizontal and vertical. This is practically a confirmation of the original view (11) Problems connected with stability :-(i.) matheof Falconer, who regarded Plagiaulax as related to Hypsi-matical investigation of stability : (ii.) the stability of aero prymnodon (Potorus). Cope (who was followed by Mr. curves of different section and of different plan (Turnbull's Lydekker on p. 193 of the fifth volume of the “ Catalogue experiments); (ii.) effect of stabilising planes and investiga

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tion of questions as to their size and position; (iv.) effect (ii.) A whirling table of about 70 feet diameter. For of rudder action ; (v.) effect of gusts of wind ; (vi.) investi- this a special building is being erected; the table itself gations as to stability of models for different dispositions is under construction in the laboratory. It will be of weight, &c.

employed for a repetition of Dines's and Langley's experi(12) Materials for aëroplane construction.

ments, as well as for propeller tests, which are urgently (13) Consideration of different forms of aëroplane, mono- called for. plane, biplane, &c.

(iii.) Two wind towers for experiments in the open. (14) Other forms of heavier-than-air machines, heli- These will enable some of the air-channel experiments to copters, &c.

be repeated on a larger scale in the natural wind, and 111.- Propeller Experiments.

will, it is hoped, afford valuable information as to the (15) Efficiency and the effect on the efficiency of varia-varying conditions which obtain in practice. tions in blade area, pitch, and slip.

(iv.) Apparatus for efficiency tests on high-speed motors (16) Positions relative to the machine.

up to 50 horse-power.

In addition, certain machine tools, &c., are being proIV.-Motors.

vided for workshop use. (17) Efficiency.

The evidences provided by the interim report of the (18) Trustworthiness and steadiness.

activity of the committee are gratifying in view of the (19) Materials of construction.

activity being displayed in other countries in practical (20) Design.

aviation. We notice that, on August 7, M. Sommer added

another triumph to France in this province of aëronautics. V.-Questions Especially Relating to Airships.

M. Sommer beat the world's record for length of time (21) Materials of construction, strength, &c. :-(i.) alloys,

in the air by Alying at Châlons for 2h. 27m. 155. The food, bamboo, &c.; (ii.) balloon fabrics; (iii.) wires,

record was previously that of Mr. Wilbur Wright, who, on cords.

December 31 last, remained in the air at Le Mans for

2h. 20m. 23s. (22) Production of hydrogen. (23) Gas-tightness of fabrics. (24) Detection of leakage. (25) Air resistance to ships of different form ; experi

THE MAGNETIC OBSERVATORIES OF THE ments on models :-(i.) effect of shape of ends; (ii.) effect

U.S. COAST AND GEODETIC SURVEY." ofessugth is ovariation with speed; (iv.) distribution of A LIBERAL addition made in 1899 to the funds avail. pressure as affecting , in

able for magnetic work by the U.S. Coast and position of propellers, fins, &c.; (v.) total resistance of Geodetic Survey enabled a great extension to be made in models rigged to represent different balloons.

the direction of magnetic observatories. Previously to that (26) Questions as to stability of airships different date the only magnetographs run by the Survey were an positions.

old Brooke instrument, first set up in 1860 at Key West, (27) Stabilising and steering appliances, fins, rudders, and an Adie instrument installed in 1882 at Los Angeles, &c.; form and position.

and subsequently in use elsewhere. These two instruments (28) General design.

are still in use, the Brooke in modified form at Vieques, (29) Navigation of airships. Mooring, &c.

the Adie at Cheltenham (fourteen miles south-east of (30) Efficiency and position of propellers for airships. Washington, D.C.), the central station of the Survey. (31) Motors for airship work.

Cheltenham also possesses

set of Eschenhagen

instruments, and similar instruments were also obtained VI.-Meteorology.

for Baldwin, Sitka, and Honolulu. The curves from the (32) General information relating to variations of wind

five observatories are tabulated at a central office, and the velocity and phenomena connected with gusts of wind.

volumes containing the earliest years' results have recently (33) Relative variation in speed and direction of the appeared. The material is dealt with after a uniform wind at different heights above the earth's surface.

plan. Each volume discusses the buildings and instru(34) Vertical movements in the air.

ments,

and

enumerates the base-line and scale-value (35) Rotary movements in the air.

changes. It is interesting to learn that the experience at (36) Electrical phenomena.

Cheltenham “ is decidedly favourable to the old Adie type, (37) Formation of clouds, snow, hail, &c.

on account of its greater stability and the less frequent Eventually the committee decided that the following

adjustments required.” Another instrumental point of researches should be undertaken at once :

interest relates to the temperature coefficients of the hori(a) Experiments on air resistance and on air friction as

zontal force instruments. That of the Adie instrument outlined in (1) to (7) above, and including experiments on

appears exceptionally large for an instrument of its type, models of airships and aëroplanes, resistances of wires and but it is less than half the average value for the four connecting stays, &c.

Eschenhagen instruments, and only one of the latter is (b) Motor tests.

worse than the Brooke in this respect. When a rise of (c) Propeller experiments.

1° C. in temperature produces the same effect in the trace (d) Tests for gas-tightness of materials suitable for

as a fall of 17 y in the force-as seems to be the case at dirigibles.

Honolulu-satisfactory elimination of temperature effects (e) Experiments on the behaviour of different materials

must be troublesome. If the cause lies in the quartz-fibre with reference to the accumulation of electrostatic charge,

suspension, a substitute should be sought for. and generally as to means of protecting airships from the

The greater part of each volume is devoted to the hourly effect of electrical discharges.

readings from the

Declination and horizontal The interim report points out that additions to the

intensity results are given for all the stations, but vertical existing buildings at the National Physical Laboratory

intensity results only for Cheltenham. Mean hourly values have been found necessary to provide space for part of the

are deduced for each month, first from all the days, and, experimental work, while a special building is also being

secondly, from the ten least disturbed days. The latter provided for the whirling table referred to below. The

form the basis of the regular diurnal inequalities given equipment which is now being installed comprises the

for each month. Inequalities are calculated for the following :

northerly and easterly components as well as for declina(i.) A wind channel 4 feet square and about 20 feet long,

tion and horizontal intensity, and at Cheltenham for dip with a fan giving a draught of 40 feet per second, special

as well as for vertical intensity. Under the heading arrangements being made to obtain a uniform flow. . This Daily Range of Declination" we have tables of values will be employed for the determination of the air-pressure 1 Results of Observations made at the Coast and Geodetic Survey Mag. components on plane and curved surfaces, for the resist- netic Observatories, Cheltenham. Maryland, 1901-4. pp. 206; Baldwin, ance of models of airships and aëroplanes, and for observa

Kansas, 1901-4, pp. 138 ; Sitka. Alaska, 1902-4, pp. 129; near Honolulu,

Hawaii, 1902-4, rp. 130; and Vieques, Porto Rico. 1903-4, pp. 70. By tions on the centre of pressure, frictional resistance,

Daniel L. Hazard, Computer, Division of Terrestrial Magnetis.n. (Wash. stability, &c.

ington : Government Printing Office, 1909.)

а

new

curves.

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