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raid properties that are the very foundations of its development in the higher centres. Some eminent physiologists now maintain, on the strength of these experiments, that the accepted doctrine of reflex action is quite untenable, and that the spinal cord is really endowed with sensation ami volition ; and certainly these adapted actions seem to give us all the signs of being felt and willed, except telling us that they are so. Before accepting, however, this explanation of the obscure by something more obscure still, it were welt to realise distinctly how dangerous a practice it usually is to apply deductively to the interpretation of Dimple phenomena ideas pertaining to the more complex, and how essential a principle of the method of induction it is to follow the order of evolution, and to ascend from the interpretation of the simple to that of the complex. The explanation savours of the old and evil tendency which has done so much harm in philosophy, the tendency to explain the facts of nature by what we feel to go on in our minds; because we know that most of our actions take take place consciously and voluntarily, we can hardly help thinking that it must bo the same in the frog. Might we not, however, as well suppose and hold that positive attracts negative and repels positive electricity consciously and voluntarily, or that in the double decomposition of chemical salts one acid chooses voluntarily the other base? It is most necessary to be on our guard against the danger of misapplying ideas derived from internal observation of the functions of miud centres to the interpretation of the functions of lower nerve centres, and so of misinterpreting them. Assuredly we have sad experience enough to warn us against involving the latter iu the metaphysical haze which still hangs over the functions of the supreme centres.

All the conclusion which the facts warrant is that actions for a definite end, having indeed the semblance of predesigning consciousness and will. may be quite unconscious and automatic ; that the movements of the decapitated frog, adapted ap they are to secure its well-being, arc no more evidence of intelligence and will than are the movements of coughing, sneezing, and swallowing in man. In the constitution of the animal's spinal cord are implanted {the faculties of such movements for self-preservation, which it has inherited as a part of its nature, and without which it could hardly live a day; accordingly it acts necessarily and blindly; though it has lost its foot, it. endeavours vainly to act as if its foot was still there, and only when the irritation continues unaffected by its futile efforts makes, in answer to it, those further reflex movements which are the physiological sequences of the unsuccessful movements: it supplements one series of reflex actions by another. But although these purposive movements are not evidence of intelligence and violition in the spinal cord, it is another question whether they do not evince the same physiological properties and the operation of the Baino laws of evolution as govern the development of intelligence and will in the higher centres.

I have taken the experiment on the frog to exemplify the proposition that designed actions may be unconscious and automatic, b< cause the phenomena are more aimple iu it than in man, and more easy, therefore, to be uuder^tood; but the proposition is equally true of his spinal cord. In its case, however, we have to bear in mind that faculties are not innate to the same degree and extent as in the lower animals, but have to be acquired by education—to be organised, in fact, after birth. It must be taught, just as the brain must, before it can perform its functions as an organ of animal lifo; and being mnch more under the control of the more highly-developed brain, feeling and volition commonly mingle largely in its functions, and its independent action cannot be so plainly exhibited. But when it3 motor centres have been taught, when they have g lined by education the power of executing what are called secondary automatic acts, it is certain ihnt it can and does habitually execute them independently of consciousness and of will. They become as purely automatic as are the primitive reflex acts of the frog. To the statement, then, that actions bearing ttio semblance of design may be uc.eonseious and automatic we liavo now to add a second and most weighty proposition— namely, that acts consciously designed at first may, by repetition, afterwards became uncon

* Two lectures delivered at the Koyal College nf Physicians in 1870. By Henry Mai-dsley, M.D., F.tt.C.t'., Professor of Medical -Hrisprudcw* iu University College, Luuduu.

scums and automatic, the faculties of them being organised in the constitution of the nerve centres, and they being then performed as reflex effects of an external stimulus. This, as we shall see, is a most important law in the development of the higher nerve centres.

Let ns now go a step further. The antomatio nets, whether primary or secondary, in the frog or in the man, which are excited by the suitable external stimulus, may also be excited by an aot of will, by an impulse coming downwards from the brain. When thiB happens, it should be clearly apprehended that the immediate agency of the movements is the. same; it is in the motor centres of the spinal cord j the will does not and cannot act upon the nervo fibres of each muscle individually, but simply gives the order which sets in motion the organised machinery of the movements in the proper motor centres. This is a consideration of the utmost importance, for it exhibits how great a part of onr voluntary acts is really the automatic action of the spinal cord. The same movements ore effected by the same agency in answer to different stimuli—in the one case to an external stimnlns, in the other case to nn impulse of will ; and in both cases the mind is alike ignorant how they are done. But while the automatic acts take place independently of will, the will is absolutely dependent on the organised experience in the cord for the accomplishment of its acts; without this it would be impotent to do a voluntary act. When, therefore, we have taken out of a voluntary act the large part which is due to the automatic agency of the motor centres, it cloarly appears that we have subtracted no small proportion from what we are in the habit of comprising vaguely under mind. We perceive, indeed, how indispensable an exact and faithful observation of the functions of the spinal cord is to a true physiological inquiry into mind, and what an important means of analysis a knowledge of thoin yields us. Carrying the knowledge so gained into onr examination of the functions of the higher nerve ceutres, we observe how mnch of them it will serve to interpret. The result is that we find a great part of the habitual functions of tbo higher centres to be similarly automatic, and to admit of a similar physiological interpretation.

There can be no doubt that the ganglionic nuclei of the senses—the sensorial nuclei—are connected with motor nuclei; and that we have in such anatomical arrangement the agency of a number of reflex movements. Most of the instinctive acts of animals are of this kind, the faculties being innate in them. In man, however, who is actually the most helpless, though potentially the most powerful, of all living creatures, when he conies into tho world, the sensory aud associated motor nuclei must be educated, just as the spinal centres must. To illustrate this sensori-motor or instinctive action, wc may tako the results of Flourens' well-known experiment of removing the cerebral hemispheres of a pigeon. What happens? The pigeon seemingly loses at once all intelligence and all power of spontaneous action. It appears as if it were asleep; yet, if thrown into the air, it will fly. If laid on its back, it struggles on to its legs again; the pupil of the eye contracts to light, and, if the light be very bright, the eyes are shut. It will dress its feathers if they are ruffled, and will sometimes follow with a movement of its head the movement of a candle before it; aud, when a pistol is fired off, it will open its eyes, stretch its neck, raise its head, and then fall hack into its former attitude. It is quite evident from this experiment that general sensibility and special sensations are possible after the removal of the hemispheres; bnt they are not then transformed into ideas. The impressions of senso reach and affect the sensory centres, but they are not intellectually perceived; and the pioper movements are excited, but these are retiex or automatic. There are no ide.is, there is no true spontaneity r and the animal would die i f hunger before a plateful of food, though it will swallow it when pushed fur enough into its mouth to come within the rau-e of the reflex acts of deglutition. Here again, then, we have a surprising variety of adapted actions of which the body is capable without the intervention of intelligence, emotion, anil will— without, iu fact, mind in its exact sense having any part in them. Tho pigeon is brougkt to the level of the invertebrate, which have no higher nerve-centres than sensory ganglia, no centres of intelligm.ee and will, and which execute nil their varied and active movements, all their wonderful

displays of instinct, through sensory and asgo-> ciated motor nuclei. They seek what is good for them, avoid what is hurtful to them, provide for the prorogation of their kind—perform, indeed, all the functions of a very active life without knowing that they are doing so, not otherwise than as our pupils contract to light, or as our eyes accommodate themselves to vision at different distances without consciousness on onr part. The highest specialisations of this kind of nerve-function are displayed by the ant and the bee; their wonderful instinctive acts show to what a degree of speoial perfection sensori-motor action may be bronght.

Unlike the bee and the ant, man must slowly learn the use of his senses and their respondent movements. This he does by virtue of the fundamental property of nerve centres, whereby they react in a definite way to suitable improssions, organically register their experience, and so acquire by education their special faculties. Thus it is that many of the daily actions of our life, which directly follow impressions on the senses, take place in answer to sensations that are not perceived—become, so to speak, instinctire ,• some of them being not a whit less automatic than the instinctive acts of the bee, or the acts of the pigeon deprived of its hemispheres. When we move about in a room with the objects in which we are quite familiar, we direct our steps so as to avoid them, withont being conscious what they are, or what we are doing ; we see them, as we easily discover if we try to move about in the samo way with our eyes shot, but we do not perceive them, the miud being fully occupied with some train of thought. In like manner, when we go through a series of familiar acts, as in dressing or undressing ourselves, the operations are really automat io ; once begun, we continue thom in a mechanical order, while the mind is thinking of other things ; and if we afterwards reflect upon what we have done, in order to call to mind whether we did or did not omit something, as for instance to wind up our watch, we cannot satisfy ourselves except by trial, even though we had actually done what we were in doubt about. It is evident, indeed, that in a state of profound reverie or abstraction, a person may, as a somnambulist sometimes does, see without knowing that he. sees, hear withont knowing that he hears, and go through a serieB of acts scarcely, if at all, conscious of them at the time, and not remembering them afterwards. For the most dislinctdisplay of Bensori-motor action in man, it is necessary that his cerebral hemispheres, which are so largely developed, and intervene much in the functions of the subordinate centres, should be deeply engaged with their own functions, or that these should be suspended. This appears to be the case in those brief attacks of epileptic unconsciousness known as the petit mal, in which a person will sometimes go on with the work he was engaged in at the time of the attack, utterly unaware of the momentary interruption of his consciousness. There are many instances of this sort on record, which I cannot stop to relate now; they prove how large a part sensori-motor functions, which are tho highest nerve functions of so many animals, play in onr daily actions. We ought clearly to apprehend the fact that, as with the spinal cord, so hero, the movements which take place in answer to the stimulus from without may be excited by the stimulus of the will descending from the hemispheres, and, that, when they are so excited, the immediate agency of them is the same. The movements that are outwardly manifest are, as it were, contained inwardly in the appropriate motor nuclei; these have been educated to perform them. Hence it is that, when the left corpus striatum is brokou up bydisease, the right caunot do its special work; if it could, a man might write with his left hand when his right hand was disabled by paralysis.

Thus much, then, concerning our sensori-motor acts, When we have yielded np to tho spinal coru all the part in our actions that properly belongs to it, and to the sensory ganglia and their connected motor nuclei all the part that belongs to them, we have subtracted no inconsiderable part from the phenomena which we ar« in the habit of designating nieutal, aud including under mind. But wo still leave untouched the highest functions of the nervous system—those to which the hemispherical ganglia minister. These are the faiiotions of intelligence, of eirotion, and of will; they are the strictly mental functions. The question at once arises whether wo have to do in these supremo centres with fundamentally different properties and different laws of evolution from

those which belong to the lower nerve centres. We have to do with different functions certainly; bnt are the organic processes which take place in them essentially different from, or are they identical with, those of the lower nerve centres? They appear to be essentially the same : there is & reception of impressions, and thore is a reaction to impressions, and there is an organic registration of ihe effects both of the impressions and of the reaetious to them. The external stimuli do not, it is true, ascend directly to the supreme centres as they do the spinal centres aud the sensory centres ; they are transmitted indirectly through the sensory ganglia; it is through the seoses that we get our ideas. This is in accordance with the anatomical observation—which, however, is disputed—that no sensory fibres go directly throngh to the hemispheres, and no motor fibres (tart directly from them; both gensory and motor fibres stopping at the corpora striata and thslami optici, aud new fibres connecting these with the hemispheres. But this does net alter the fundamental similarity of the organic processes in the higher centres. The impressions which are made there are the physiological conditions of i/leas. The feeling of the ideas is emotion; for I hold emotion to mean the special sensibility of the vesicular neurine to ideas. The registration of tbem is memory; and the reaction to them is volition,. Attention is the maintenance of the tension of an idea or a group of ideas—the keeping it before the mind; and reflection is the successive transference of energy f rpra one to another of a series of ideas. We know not, and perhaps never shall know, what mind is ; but we ure nevertheless bound to investigate, in a scientific spirit, the laws of its functions, and to trace the resemblances which undoubtedly exist between them aud the functions of lower nerve centres.

(To be continued.)

STRENGTH OF MATERIALS. By A. Totjiattsen, Jro. (Continued from page 124.) "T is not every kind of tar that destroys

the durability of the fibres, for the Archangel and Stockholm are said to preserve the rope, so that in the execution of important works it is recommended that the ropes should have been recently manufactured, and be made of the best Petersburg hemp, with Arohaugol aud Stockholm tar.

The tar applied to ropes made by the warm register is more fluid than in those made up with the yarns cold, and therefore penetrates every fibre of hemp completely. Again, as the heat drives off both air and moisture, each fibre is brought into closer contact by the twisting and compression of the strand, and the strength of the rope is greatly increased. Another advantage is derived from the warm register, as ropes made by the same are almost impermeable to water, so that it is absolutely necessary in places where they are exposed to the wear and tear of the weather to have them made by the new process.

The dimensions of ropes are generally'stated in terms of their girth or circumference, and worked to about one-sixth of their breaking strain. The weight of hempen ropes (in lbs. per fathom) is approximately found by multiplying the square of their circumference by 26.

Flat ropes, made by placing four round ropes Bide by side, and stitching them up by machinery into a flat band, are now used for many purposes where great lengths or depths, such, for instance, as in raising coal from pits, have to be attained.

They possess great strength and flexibility. In some cases, if ropes were applied they would be cut to pieces in a very short time, "and the weight of chains might also be inconvenient ;it is in such instances that wire ropes are used, and have proved to answer the purpose very well in working inclined planes, &c. On the DnrhamSunderland railway, train" are drawn np and let down an inclined plane of 4£ miles length by means of an endless wira rope, made of three pieces.

The two practical rules for computing the strength of ropes are sometimes enunciated to be :—

To find the breaking weight in tonB of a rope made of common hemp, multiply the square of the circumference (in inches) by -288; conversely to find the circumference (in inches) of a hempen rope whose ultimate strength is given; extrac

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Rigidness Op Ropes And Strains.

Till now we have considered ropes and chains to be perfectly pliable, which, however, in practice is not the case; for daily experience shows that any ropo of ordinary dimensions requires a certain amount of force to be applied to twist it in any direction, and this foroe is called the stiffness, or rigidness of that rope.

It is obvious that this foroe will chiefly depend on the intensity of that force W stretching the rope, on tho radius of curvature, and the thickness of the rope itself. Again, it will depend on the material of which tho rope is made, on the number of fibres and twists given to the same, as well as whether the rope is new or old, tarred or unlarred.

Amontonf and Coulomb (celebrated French engineer, born 173(5 in Angouleme, and received tho first prize of the Paris Academy of Sciences for his "Tlieorie des Machines Simples ;" died in 1806) were the first who investigated this foroe, and the experiments of tho latter, which follow, led him to the mathematical formula :—

(1.) Bn = (+ J> W)

2r

Whereby S is the registry of the rope, S the diameter of the same, r the Tadius of curvature; n an integer; a co-efficient, both varying with the quality of the rope, and b a magnitude merely

* "Molesworth's Eugineeriu Pocket

V iz., Prof. Ru hlman's " Mechnnick," p. 250.

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approaohing value by I—I whereby J" is the of the rope whoso rigidness is reaccording

1 to

diameter quired.

The power n varies from to finality and strength of the rope.

The same found also that ropes, when moist, possess less rigidness when of large diameter, and greater stiffness when of small dimensions.

But although rope made by the warm register is both stronger and more durable, it is less pliable, and therefore the cold-registered [rope is more generally used for ctane-work, where tho rape must be wound round barrels and passed through pulleys, as in these cases the radius of curvature is very small.

A formula more applicable to practical purposes is one proposed by Eytelweinf and symbols lically demonstrated by

S' 1 S = B —W r r being tho radius of barrel -f- half the rope's diameter.

When S and r are given in metres and W in kilog., R = 18, and then we have S* 1 S = 18 — W r Redtenbacher proposes to use when S and r are in terms of centimeters

S = 0-20 — Wa
2r

If instead of a rope, a chain be wound on a barrel of radius r, then the friction acting at the links has to be added to the stretching load. If the diameter of a link be represented by S, and the coefficient of friction by/, then we may write for the statical moment ot rigiduess S,

S»- = if iW.

For the statical moment, however, of the force P, overcoming this resistance of the chain

Pr = W(r+l/o).

Nevertheless, as the cliain has to become straight on the other side, wc may assume the momout of the whole to be

Pr = W(r+|/J) , which may, for practical purpose!, be written P = W(r+/o).

WeisbachJ, who made several experiments on the flexibility of wire rope?, found

W S = (0-49 X 000238 — kilog. r whereby r was given in metres.

Experiments made in Germany (Froiberg§) have shown' that the rigidness of wire ropes, in being drawn over barrels is almost overcome by the following formula :—

I) = 0-24 S* V whereby D is tho diameter in feet, S the diameto of the wire used in millimetres, and H the number of threads the rope is composed of.

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By means of tin's formula wc may now "ive an example of its application.

Example:—What is the intensity of rigidness in an nntarred rope of 0023 met. diam, wound round a barrel 0-28 met. radius, and sustaining a werght=400 kilog? b

OurFormula 1 gives: (0-023)

S = 18 x x 400 = 12-96 kilog.

0-28 x 0011

MECHANICAL MOVEMENTS.

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2747

S = = 9-44 kilog.

0-291 This result is smaller than the first, and as it is better to calculate the strain larger than it actually lain practice, Formula 1 may with advantage be adapted.

MECHANICAL MOVEMENTS.*
(Cjntinucd from page 177.)

Q1 Arnold's chronometer or free csenpe-
«/X. ment, sometimes used in watches. A
spnug A is fixed or screwed against the plato of
the wateh at b. To the under side of this spring
is attached a'small stop d, against which rest
successively the teeth of the escape wheel B; and
on tho top of spring is fixed a stud i, holding a
lighter and moro flexible spring which passe*
under a hook k, at the extremity of A, so that it
isi tree on being depressed, but in rising would

* J °TM the Bxi'1 of tho ba'ance is a small

stud a, which touches the thin spring at each
oscillation of balauc-wheel. When the move-
ment is in the direction shown by the arrow, the
stud depresses the spring in pissing, but' on
returning raises it and the spring A and stop d,
and thus allows one tooth of escape wheel to pass
letting them fall immediately to arrest the next
At the samc^time that this tooth escapes, another
strikes against the side of the notch a, and re-
stores to balance-wheel the force lost during a
vibration. It will be understood that only at one
point is the free movement of balance opposed
during an oscillation.
92- Stud escapement, used in large clocks.

Kdlto^nT^L1 rHnm a ""rapilation by Mr. II. J. Brown
Jvuiior ot the Amencau Artisan.

One pallet B, works in front of the wheel and the
other at the back. The studs are arranged in the
same manner, and rest alternately upon the front
or back pallet As the curve of the pallets is an
arc described from F, this is a repose ot dead-beat
escapement.

93. Duplex escapement, for watches, so called
from partaking of the characters of the spur and
crown wheels. The axis of balance carries pallet
B, which at every oscillation receive, an impulse
from the crown teeth. In the axis A of balance-
wheel is cut a notch into which the teeth round
the edge of the wheel successively fall after each
one of the crown teeth passes the impulse pallet B.
J4 and W. A cylinder escapement. 94 shows
the cylinder in perspective, and 95 shows part of
the escape-wheel on a large scale, and represents
the different positions taken by cylinder A B
during an oscillation. The pallets a b c on the
wheel rest alternately on the inside and outside
of cylinder. To the top of cylinder is attached
the balance-wheel. The wheel pallets are bevelled
so as to keep up the impulse of balance by sliding
against the bevelled edge of cylinder.

9G Lever escapement. The anchor or piece
B which carries the pallets, is attached to lever
H L, at one end of which is a notch B. On a disc
secured on the arbor of balance is fixed a small
pin which enters the notch at the middle of each
vibration, causing tho pallet to enter in and retire
irom between the teeth of escape-wheel. The
wheel gives an impulse to each of the pallets
alternately as it leaves a tooth, and the lever
gives impulse to the balauce-wheol iu opposite
, directions alternately.

97. An escapement with a lantern wheel. An
arm A carries the two pallets B and C.

98. An old-fashioned watch escapement.

99. An old-fashioned clock escapement.
100 and 101. A clock or watch escapement •

100 being a front elevation, and 101 a side eleva-
tion. Tne pallet is acted upon by the teeth of
one and tho other of two escape-wheels alter-
nately.

102. Balance-wheel escapement. C is the
balance; A B are the pallets; and D is the
escape-wheel.

103. A dead-beat pendulum escapement. The inner face of the pallet E and outer face of D are concentric with the axis on which the pallets vibrate, and hence there is no recoil.

104. Pin-wheels escapement, somewhat resembling the stud escapement shown by 92. The pins A B of .the escapement wheel aro of two different forms, but the form of those ou the right side is the best. One advantage of this kind of escapement is that if one of the pins is damaged it can easily be replaced, whereas if a tooth is damaged tho whole wheel Is rained.

105. A single-pin pendulum escapement. The escape-wheel is a very small disc with single ecceutric pin; it makes half a revolutioa for every beat of the pendulum, giving the impulse on the u origbt faces of the pallets, ihe horaont&l faces of which are dead ones. This can also be adapted to watches.

(To be continued.)

DRESSING MILLSTONES WITH THE
DIAMOND OK "BORT."

(Cotu-luded from page 179.)

FIO. 8 is a plan of the dressing apparatus as applied upon a millstone, and Fig. 9 is a corresponding vertical section. Fig 10 is an inverted plan of the bottom of the tool or bort holder and Figs. 11 and 12 are an end and a front elevation of the slide as fitted with a single tool; whilst Figs. 13 and 14 are sectional elevations of a modification of the slide fitted with two tools.

The framing of the machine consists of a central boss 1, made hollow to go over the head of the millstone spindle when operating on the bed stone, and this boss is connected by arms 2, to a segmental • ring 3, accurately turned, or otherwise made flat on its undersido to rest on the surface of the millstone 4, near the outer edge thereof, that being the part of the millstone surface that can be most relied upon as being truly level. To facilitate tho placing of the frame ou the st.me three adjustable claws 5, are fixed on the segmental ring 3, and citch upon the top binding hoop; accurate centering, however, of the frame ou the stone is not essential. Two of tho frame arms 2, are made in the same line tangential to the boss, and to them there is fixed a horizontal guide 6, made with V rails to receive a saddlo 7, which can be moved along the guide 6, by ineaus of a screw spindle 8. A horizontal arm 9, is fixed to the saddle 7, so as to stand out at right angles from the guide G, and this arm is) made with horizontal V rails to guide a slide 10, in which is adjusted the tool or bort holder 11. The bort holder 11, is a spindle screwed at its upper end to receive a nut, and formed at its lower end with a cross plate to fit a rebate m the bottom of the slide 10, and with a boss m which a socket is bored to receive three angular steel bits by which the bort is fixed. The three steel bits are shaped to build together into a cylindrical form a little1 less than the >ocket, and the bottom comers of their central meeting edges are hollowed to griip the bort, whilst they are adjusted upon it by screws tapped through the tides of the socket. With this simple con

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DRESSING MILLSTONES WITH THE DIAMOND OR " BORT."

etruotion tho bnrt tin be gripped in any position by the steel bits, and the whole can be turned in the socket so as to present the cutting angle of the bort in the most advantageous manner. One or two pieces of vulcanised rubber a are applied between the bottom cross plate of the tool 11, and the slide 10, and may be more or less compressed to modify the elasticity of the tool by means of the screw nut which holds the tool in the slide. A handle 12, is jointed upon the slide JO, and by means of it the operator draws the slide along the guide arm 9, and so causes the bort to cnt a minute groove on the surface of the millstone. The dressing for one sector of the millstone surface is done with the frame 12 3, in one position, the arm 9, being shifted or fed across after the formation of each groove by means of the screw spindle S. Toothed feed wheels 13, are fixed on the ends of the screw spindle 8, and are acted upon by feed catches jointed to levers 1-1, set loosely on the spindle and connected by means of a horizontal rod 15, above. A handle 16, is set loosely on the rod 15, so that it can be moved into the most convenient position for the operator, who works the tool slide 10, with one hand, and the feed handle 16, with the other. The feed may be effected either when the slide 10, is at the inner end of its traverse, or when it is at the outer end thereof, the bort being moved in both directions along each groove; or the feed may be effected both when the slide is at the inner end and when it is at the outer end of its traverse, in which case the bort will be moved only once along each groove. When the dressing of one sector of the millstono surface is completed the entire machine is shifted round, to bring the arm 0, parallel to the grooves of the next sector.

Two borts with their holders may be carried on the slide 10, as shown in Fig. 14; and this modification may be used when the deeper cut is required than that which a single bort will give, one of the two borts being adjusted slightly lower than the other. When applying two tools in this way the spindles are fitted somewhat loosely into the slide 10, and small cushions b of vulcanised rubber are placed behind them, whilst small pinching screws c are inserted in front, and by turning those more or less the two bort

points can be adjusted so as to cnt accurately in the same line. The two tools may also be adjusted to cut in two separate lines if preferred. A comparison with Golay's machine will render obvious the superior construction of Young's, its remarkable simplicity, and its freedom from various drawbacks associated with the earlier machines. The dress or cracking which Young's puts into the millstone, consisting of straight horizontal cuts, is cleaner and neater, and has not the ragged or fractured appearance caused by tlfe chipping action of the rotating tool. It is especially superior in indicating and discovering any inequality or want of truth in the grinding surface, doing this with a precision and accuracy not hitherto attained, and which necessarily arises from the machine being formed with a turned bearing ring, which rests on a large portion of the millstone surface near the outer edge. This is confirmed in practice by the machine discovering many imperfections of surface which the prov- F.c.io

ing staff allows to escape notice. Requiring no driving power, it can be worked whether the mill is running or standing. It requires no gearing whatever, and is much less dependent on individual skill, as it can be actuated by a lad or inexperienced workman. It cannot get out of order. It dresses the stone in less time than Golay's, and, as compared with ordinary handwork, requires the service of fewer stonemen. Immediately that the stone is set to work after being re-dressed, it grinds perfectly, making much fewer flour sharps, or middlings, and, in consequence, a larger proportion of fine flour. The bran is broader and better cleaned, and the flour of purer colour and more regular. The amount of feed, or rate of grinding, is not decreased ; whilst, in consequence of the ease and rapidity with which the operation can now be effected, the millstones are sometimes re-dressed after running four days and nights. This more frequent ro-dressingis found advantageous where the mixture of wheat is soft and tough, but where it is dry the stones are rc-dressed only after

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running six days and nights. When the stones are lifted for re-dressing they are found to be in perfect trim, having a beautiful straight level face, and with much of the former dressing still dear and distinct. One miller using Mr. Young's machine found, on a careful comparison with the results of the ordinary handbill dressing, that out of every hundred boll of wheat (1 boll = 2401b.) he obtained a bag and a-half, equal to 4201b., more fine flour, with proportionally less seconds.

A great variety of millstone dressing machines have been brought out and patented since tin su to which we have referred, but they are all comprised in the "rotatory" and "rectilinear" classes, of which Golay's and Young's are respectively the chief representatives ; and they differ amongst each other mainly as regards minor details, a critical comparison of which would not only be tedious and uninteresting, but it is also incapable of being satisfactorily made at present on account of the small experience as yet had with most of them.

Naturally, where several patented machines for the same purpose compete, questions must arise as to the novelty and validity of each, and as to whether the more recent are infringements of the earlier patents. The main competition is practically between the two most successful machines, Golay's and Young's; and we believe that tho U'reat hindranco to the more general adoption of one or other of these machines has been the doubt whether Golav's patent is valid, and whether Young's machine, as has been openly asserted by persons interested in Golay's patent, is an infringement of it. At the same time many of the most extensive millers in the United Kingdom have adopted one or other of the machines, convinced of the great superiority of the dress over hand dress. As regards the diamond itself, Golay does not claim to use the diamond except when acting with rapid blows, and clearly could not validly claim the plain, continuous, rectilinear cut of the diamond in face of the earlier patents of Childs and Knight j whilst as both Young and Golay are obliged to use bort instead of the common clear diamond, it is plain neither of them is clear of .lobin's patent. As regards the necessary apparatus, Young's only resembles Go'aj 's in having B horizontal guide and slide with a screw feed motion at right angles thereto; but in thin respect both Golay's and Young's roseuible -Morisscau'B, whilst Young's arrangement is in fact more like Morisseau's than it is like (Jolay's. We will not take upon us to certify how the lawyers will decidfrthe questions, but they appear to us very simple ones, and plain common sense answers to them sufficiently obvious.

Wo have applied the term "bort" to the substance Dow used for dressing millstones, as being the best and most distinctive appellation without coining a new word; it is, however, also used to designate tho impure fragments and excrescences which are removed from the rough diamond in the process of cutting, and which are not so hard or suitable as the stones originally found in a detached state.

The End.

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IT is said the invention of C. W. Peterson, of No. 7, Oakley-crescent, City-road, London, for tho application of steam power to lifeboats, is destined to effect an important improvement in our lifeboat system, and consequently to increase very considerably the means at our disposal for saving life at sea. The Committee of the Shipwrecked Mariners' Society, after examining the models and drawings of the invention, have expressed themselves pleased with it, and are anxious that it should have an adequate trial. Captain Peterson is confident that his boat will bo able to,put to sea in all weathers, and that, if upset, it will instantly right itself without losing its motive power. The advantage it will possess, both in respect to increased speed and power, over the lifeboats now in use must, of eonrse, be self-evident, but the great thing is to put the invention to the test. The cost of building a trial boat will be about £600 er £700, towards which the Committee of Lloyd's have subscribed £50, theSalvas:eInstitutionin£52108.,the8hipwrecked Mariners' Society, £50, the Royal National Lifeboat lustitation £100, Miss Burdett Coutts £100 and about £50 has been contributed by merchants and others, making altogether upwards of £400. The names here mentioned as subscribers afford a guarantee for the practicability of the proposal, and we trust their liberality will at once be supplemented to such an extent as to insure the complete realisation of Captain Peterson's intentions. The object is one of such national importance that it ought to command universal sympathy and support, and to be received with special favour and interest by maritime communities directly concerned in the welfare and safety of our seamen. This being so, Captain* Peterson may reasonably expect such an amount of assistance—and that, too, within a very short time—as will enable him to put his invention to the test.

We should like to know what Mr. Lewis, the zealous Secretary of the Royal Lifeboat Institution, or any one else who has paid attention to the subject, has to say about these lifeboats. If the thing be practicable, we see no reason why |the English Mechanic Lifeboat should not be propelled on its beneficial errands by steam.

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{Continuedfrom page 175.)

LET us see how far this dreadful programme is in reality carried out nowadays, by glancing at the following results of our analysis. But before doing so, we will explain the simple process we have adopted for obtaining onrresultB. The mode of procedure does not pretend to absolute accuracy to a fraction, but will be found in practice cosily performed and understood. It is as follows :—

1. Twenty grains of the cocoa are woighed out and dried for some hours at a steam heat. The dry cocoa is then weighed, and the loss of weight, multiplied by 5, gives the moisture,

2. The residue (from 1) is digested for two hours, with frequent agitation, in four ounces of other, and the latter having been poured off as closely as possible, the cocoa is again dried, weighed, and the loss of weight ascertained aud calculated as above. Tho loss equals fatty matterg.

3. The residue (from 2) is digested for six

• By J. iluTEn, Fij.D., ia the Food Journal.

hours in ten ounces of cold water, and again dried and weighed as before. This loss represents sugar, theobromine, and other soluble constituents ; and it is evident that if sugar of adulteration be present, the loss of weight will be greatly increased.

4. The residue (from 3) is boiled for an hour in ten ounces of water, to which half an ounce of hydrochloric acid has been added, and once more dried and weighed. The loss in this case consists of starch, cocoa red, &c.,and here the starch which has been purposely added is discovered.

5. A few grains of the cocoa are burned on a crucible lid, and the colour of the ash is observed. If this be decidedly red, then ochre or some such colouring matter has been employed.

As we have already remarked, although the process cannot pretend to absolute truth, yeto very close approximation can be thus obtained, especially if samples of pure cocoa be first treated in an exactly similar manner. This we have done and the following results represent an average of several such experiments:—

Moisture 45

Soluble in ether (fat) ... 48-5
Soluble in water (sugar, &c.) 11-8
Soluble in acid (starch, Sec.) 188
Residue insoluble (csllulose,&c.) 164

1000

The colour of the ash was a light grey, and no foreign starch was visible under the microscope. With this explanation we proceed to the

Analysis of Thirty-one Samples of Cocoa.

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It will thus be seen that, out of all the samples examined, the only one which answers to the analysis of pure decorticated cocoa is No. 81. Nos. 2 and 34 are, however, also good samples of cocoa, while Nob. 11 and 12 must be noted as specimens of pure cocoa deprived of its oil. No. 1 is a pure cocoa to which desiccated milk has been added, thereby slightly increasing the fat and Sugar. The worst of all are Nos. 18, 19, 20, and 33, in which not only is the quantity of real cocoa reduced to a minimum, but ochre, or some such ferruginous earth, has been added for colouring. On the whole, the picture is one not calculated to reassure the the cocoa-consuming portion of the public. We append recipes for the manufacture of cocoa which would be similar to three of the most adulterated samples:—

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I Now we are brought face to face with the question: Ought this addition of starch and sugar to cocoa to be regarded as an adulteration 1 If, on the one hand, we take the word adulteration to mean the mixing of anything hurtful or deleterious with an article of food, the answer muse be in the negative, because not only is the starch harmless, but it supplies a want in tho article itself, besides diluting its rich and somewhat dyspectic qualities. Indeed, this admixture has been regarded by an eminent food authority, as "a skilful chemical adjustment, made without chemical knowledge, as the result of long and wide experience." But, on the other hand, if we take adulteration to mean the mixing of anything (even if it should be beneficial) with an article of diet, without distinctly setting forth the fact, the present style of cocoa manufacture becomes a sophistication! With the greatest desire to let this matter down gently, as we have no wish to hold almost all the cocoa manufacturers in England up to public reprobation as sophisticators, we connot escape the fact that many prepared cocoas are advertised as "genuine," nor can we help harbouring a shrewd doubt, that the comparative prices of cocoa and starch had much more to do with the "skilful chemical adjustment," than a real desire to benefit the public. We should advise the many respectable firms engaged in the cocoa trade to cull their cocoas plainly and distinctly prepared cocoas, or by some such term as would convey the true impression of their nature. This would be very much more sensible then denominating them "genuine," "soluble," or " homoeopathic," &c, when all the connection they have with solubility simply consists in the amount of soluble matter added as a diluent, and with homoeopathy in the small amount of real cocoa which they give at B dose. In a word, we are once more brought back to the necessity for an " Adulteration Act," such as «re have all along steadily advocated—namely, a law to compel everything to be sold under its own name, with proper officers to see the Act carried out; but to hope for such a thing under the present regime, seems almost Utopian; and we have no resource but to follow the dictum of an eminent statesman, and to " agitate and agitate."

In our next article we will conclude the subject by giving directions, illustrated by engravings, for the detection of adulterations of cocoa, by means of the microscope.

THE PATENT LAWS.

A SHORT time since a meeting of the Manchester Patent Law Reform Association was held, Sir William Fairbairn in the chair, when the following petition to Parliament was discussed and adopted I —

"That your petitioners Icing persons engaged in various branches of industry and commerce in the city of Manchester and the surrounding district, formed themselves, with others, in 1850 into an association for procuring a reform of the patent laws as then existing and administered, the evils of which and the remedies therefor, they set forth in memorials to the Board of Trade and petitions to Parliament in 1850,1851, and 1852, and, after incessant labour and expense, were the principal means of obtaining the Patent Law Amendment Act of 1852. That Act, although it did not adopt all the recommendations of your petitioners, provided remedies for some of the then existing evils, such as granting immediate protection to inventors on application, a large reduction in the amount of fees paid for obtaining letters patent, and the publication of all specifications and indexes thereto; but it left untouched many of the evils for which your petitioners pointed out remedies, which had they then been provided for, would have satisfied the. public and prevented the unreasonable outcry now raised for the entire abolition of the present patent laws. That your petitioners are fully of opinion that the fees may be consideraldy reduced, as they consider the cost of obtaining letters patent should not exceed what is absolutely necessary for the maintenance of the Patent Office and printing the specifications and indexes. That your petitioners, fully sensible of the advantages of a well-devised patent law, are decidedly of opinion that any attempt to abolish these laws would prove not only highly injurious to the best interests of the country, and destructive to the inventive powers of the nation, but would ultimately destroy the high position this country has attained in the prosecution of the

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