13th June 1888
From: Lord Uriah Chetworth, Cornwall.
To: Archibald Jenkins, Oxford University.
Archibald,
I hope your studies are successful, and the college is treating you well. Now that you have reached your second year, perhaps you might wish to flex some of that new engineering muscle by solving a puzzle for me. On this occasion, I do not enquire on behalf of the expedition team, but to resolve an ongoing health issue suffered by my older sister, Harriet. You and I have only been acquainted for some four years now, and so I am unsure whether you know that my older sister must wear a brace upon her right leg to support a crippled knee. Despite her advance upon her middle years, she as ever remains extremely fit and agile, but you may have noticed that she does indeed walk with a slight limp that becomes more pronounced with every passing year. This weakness she sustained when a young girl, the result of a fall from a tall tree. Although I was but a youth at the time, this accident is a misfortune for which I feel very much responsible. The rope swing that I had hung from one of the tallest trees on the estate was secured insufficiently, an error of my own for which poor Harriet paid a high price. She landed extremely badly, to crush the mechanisms of her right knee. An injury that has never fully healed.
This incident was, in fact, the very provocation of my interest in all things mechanical and ingenious. Such was my guilt over the injury that I caused a beloved sister, that my youthful optimism elected to repair the damage that I had so wrought. To this end, I retired to the boathouse, now the site of the manufactory, with tools in hand and set to work constructing for my sister a support for her malfunctioned knee. I was only a youth at the time, and my hands had not yet the skill to manufacture such a device. Regardless, that which my naivete did manage to produce functioned adequately well, for Harriet was delighted with my efforts and was sure to wear this support whenever an outdoor activity might inflame her injury. In the years that followed my practical skills grew as did Harriet's stature, and as a result, I have frequently revised my design to offer an improved support.
However, I now encounter a problem. Harriet has travelled the globe to exercise the responsibilities of her Christian mission and endured rigours to nurse those in need. Wherever on the globe a conflict may arise, there you will find Harriet in the very thick of it. There she will be found on every occasion, to render aid to the injured and to save the day. In fact, ever since she began this work at the tender age of nineteen the girl has exhibited a prodigious nose for being in just the right place at just the right time to administer such medical care. It is quite extraordinary how well she can detect the suffering of man and be there ready to render assistance. One might even imagine that she can arrive prior to such injury, to prepare her bandages and bedpans, ready to render aid the moment hostilities begin. She is an amazing woman, and it is quite beyond me why she remains unmarried to this day. Suffice it to say, her efforts have accumulated a considerable mileage upon that deficient knee, notwithstanding the many hours she must stand to assist in those surgeries permanent or makeshift. As a result, my own ingenuity may no longer be adequate to bear Harriet’s missionary virtues. In fact, Harriet has personally requested that I contact you to determine if you might turn your considerable, and now enhanced, talents to the support of her right knee? In particular, I would be very much obliged if you could visit the department of medicine, to make enquiries about those latest medical technologies that could ease Harriet’s infirmity. The dean is an old school friend, so do give him my regards should you encounter any difficulties securing an audience with the faculty.
Harriet sends her regards, and in the meantime, good luck with the studies.
Uriah
30th June 1888
From: Archibald Jenkins, Oxford University.
To: Lord Uriah Chetworth, Cornwall.
Uriah,
Thank you for your continued faith in my abilities. I have studied hard and am sure to make the best use of the endowment you offered my parents to send me to this prestigious institution. I had no difficulties to secure time with the medical faculty, for they knew precisely who I was the moment I entered the building. It seems that your reputation precedes you, and your erstwhile colleague sends his regards. Always the first step in solving any problem is to best describe the problem itself. Hence, in conversation with the medical faculty, we made a shortlist of those properties that Ms Chetworth will desire from a suitable support for her malfunctioned knee.
It is clear that the support for Ms Chetworth’s knee must resolve that most classic of engineering contradictions, to be both strong and lightweight. Furthermore, the mechanism must be comfortable to wear. In the pursuit of prior art, although I do not have much experience of the topic to draw upon, I expect that the undergarments of the fairer sex most probably exhibit precisely these properties. As a result, I at first expected that I must determine some delicate means to investigate such structures of silk and whalebone.
However, I am relieved to report that no such foray into those topics unknown may be necessary, for in this modern age a great many new materials are available to realise our objective, and it is incumbent upon those of us who seek to push the boundaries of design to exercise their properties.
I have indeed had the very great fortune to meet Miss Chetworth at the House on two of those rare occasions when she has returned home from her travels, at those soirees you organised upon our departure to and our return from our Arctic adventure of 1885. Upon our return, after some drink had been distributed, I regaled Miss Harriet with the tale of our encounter with that ferocious polar bear. Miss Harriet, also somewhat worse for wear, but bearing it well, and I might add better than many of the crew, very kindly indulged me in the telling of my tale on perhaps more than a single occasion as the evening wore on. I hope it not presumptuous of me to report my impression that Miss Chetworth is of a type who would relish the opportunity to experiment. However, I must admit that on the occasions that we have met, I had not noticed that Miss Harriet walks with a favour to one side. She must possess a considerable fortitude to hide such a chronic injury so very well.
Strong, light and comfortable are not the only properties that this mechanism must adopt. This knee joint must not only support the knee and remain straight despite Miss Harriet’s weakness. The mechanism must also bend easily to allow a natural gait and also to permit the user to sit comfortably at the opera or within a carriage. The leg must incorporate some force to remain straight, but also must become easily bent. I might expect this artificial joint to present a compromise between the two, with some spring joint or frictional bearing to prevent the hinge from rotating quickly, thus supporting the knee whilst also permitting a slow descent into a seated position. The need for these two behaviours, and hence their contradiction, are separated in time, and so we must determine some mechanism to realise this separation.
Have you drawings of the current brace? I would very much like to see how you have resolved this problem over the intervening years since Miss Chetworth’s misfortune. In the meantime, in those short periods between lectures and my studies, I shall endeavour to resolve this problem.
Archie
7th July 1888
From: Lord Uriah Chetworth, Cornwall.
To: Archibald Jenkins, Oxford University.
Archibald,
You judge Harriet well, for I suspect that she may have requested your specific attentions due to your propensity for experimentation and novelty. You also define the problem well, for I have long laboured to provide Harriet strong support and have perhaps paid insufficient consideration to the needs of a fashionable lady. Hence my efforts have been wrought from bars of steel and straps of leather. It is perhaps high time we addressed this contradiction.
The modifications I have made to Harriet’s brace have typically been extemporaneous novelties, wrought at the moment of conception. Therefore, I possess few drawings that describe the evolution of this device. The only comprehensive study was made in the early days of the house manufactory when I had but few adventures under my belt and had not yet built the commercial enterprise for which the house is now so well known. The young man who made these drawings exhibited a very fine hand, that does remind me somewhat of your own. This skill was remarked upon by my younger sisters, Charlotte and Silvia. Young women are known to frequently share their fashions and as a result, my sisters are well acquainted with our Harriet’s particular dimensions. How they long marvelled and remarked upon the skill of our young draughtsman. The fellow had successfully managed to reproduce a quite accurate likeness of the patient, despite working from only rudimentary measurements obtained from Harriet’s dressmaker to provide a reference with which to make these drawings. I will admit, the whole affair did provide some pause. How the gentleman had managed to conjure such an accurate figure is beyond me and for this figure to so vividly reside in the young man’s mind did provoke me to some disquiet. I brought this discomfort to Harriet, in concern for her dignity, but she merely commented on the young man's fine hand, his skill and his imagination and we have not talked of it since. However, their subsequent and indiscrete disagreement at the works Christmas celebration soon afterwards did result in his prompt departure from our employ.
Do ignore the old six-shooter observed in this illustration. This weapon I loaned to Harriet at her request, to afford her protection on the numerous Grand Tours of her youth. I had always intended to offer something more suitable for a lady. However, once she had returned from her travels, she had quite adopted the calibre and, I might add, had indeed expended all of the ammunition. However, despite her refusal to relinquish the weapon it remained appropriate to obscure this somewhat unsuitable artillery piece. We incorporated it into her knee support, hidden by her dress[1] but made accessible through a split in the side of her skirts[2]. The trouble I see brewing is to be found in a means to manufacture a more elegant brace. To offer a solution beyond iron bar, to propose some more delicate frame that offers sufficient strength. I suppose it is not beyond our means to simply sculpt the structure that we require from solid stock. To this end, perhaps some wooden or steel mechanism might be milled to suit our purposes. An expensive and time-consuming process, indeed, but an expense that I would be willing to bear tenfold for the comfort of my dear sister.
Uriah
Plate 1: Garza’s illustration remained a contentious issue for Chetworth throughout his life.
[1] Separation principle 30. Flexible Membranes. Thin Films. Replace components with flexible membranes or thin films. Use thin films as a barrier to isolate harms or benefits.
[2] Separation principle 7. Nested Doll. Place objects inside another object, or pass one object through another.
16th July 1888
From: Archibald Jenkins, Oxford University.
To: Lord Uriah Chetworth, Cornwall.
Uriah,
To manufacture a more elegant support will indeed require the resolution of a contradiction. After all, the solution will not only be best served with a structure of greater elegance, but my discussions with the medical faculty suggest that a structure that spreads load across the maximum surface of the wearer will result in the least pressure at any one point. Hence, the structure must not only be delicate but also match the contours of Miss Harriet's limb. For the device to fit precisely, I fear that we may require greater precision than even the fine eye of a draughtsman could manage. To this end, a mould of Miss Harriet herself must be made, around which a further mould of the device might be wrought. However, as one benefit is realised, harms are introduced, to realise a further contradiction. The manufacture of this device will require a material that can both flow into a mould, to then harden into a strong structure. The only material that comes to mind is that of iron and steel, to lead us once more back to structures better suited to a steam train rather than the skirts of a lady. We must find a material that is not only lightweight and strong but also pliable and rigid.
The latter contradiction offers a characteristic to our advantage. Whilst the final mechanism must be both simultaneously strong and lightweight, the material need not be both pliable and rigid at the same time. These properties can be separated in time. Pliable under construction, to become rigid in use. Beyond molten iron, I am aware of experimental materials of a plastic nature realised by the application of sunlight to initiate the polymerization of vinyl chloride. Perhaps their initial plasticity can be employed to realise a structure from a mould? I shall make enquiries with those chemists that I am most certain to find on the campus. Might you have some further acquaintance in the faculty for chemistry that I might approach?
With possible materials selected, we can begin to think of structures that would suit our purpose. Miss Harriet’s knee must bear weight, and yet not bear weight, for which we must introduce some mediator[3] to bear the excess, to connect thigh to shin, to bypass the knee. We must spread this load over as much surface as possible, whilst also we employ as little material as we can. To this end, I propose a porous or mesh structure to achieve both desires[4]. In conversation with the gentlemen of the medical faculty, I note that our problem incorporates an advantage not typically enjoyed by those who must fashion a prosthetic for those unfortunates for whom we must replace a limb entire. In our case, we must nest[5] Miss Harriet’s existing limb inside some supporting structure, and thus Miss Harriet herself offers support to the whole[6]. So, as our structure supports Miss Harriet’s limb, so Miss Harriet’s limb supports our structure to offer a strong composite forged from those integrated parts[7]. I enclose an illustration of a potential structure that may serve our purposes. I have yet to derive a mechanism that would act to replace the strength of the knee joint. However, might the supporting services fashioned thus serve our ends?
Archie
Plate 2: A mesh-like porous surface spreads the load over a wide area.
[3] Separation Principle 24. Mediator or Intermediate. Use an intermediate object to transfer or exercise the action.
[4] Separation principle 31. Porous Materials. Replace materials with porous substances. Fill porous materials with a beneficial substance. Use capillary action.
[5] Separation principle 7. Nested Doll. Place objects inside another object or pass one object through another.
[6] Separation principle 25. Self-Service. Allow an object to offer a benefit or remove a harm from itself. Employ waste energy or material.
[7] Separation principle 40. Composite Materials. Replace homogenous materials with composite materials.
6th August 1888
From: Lord Uriah Chetworth, Cornwall.
To: Archibald Jenkins, Oxford University.
Archibald,
Upon review of your illustration, your point is made clear. Such a structure does indeed spread the pressure of its operation, whilst the mesh structure attempts to diminish the overall weight. However, such a structure is well beyond my hands to fabricate, although I feel sure that most of the skilled gentlemen of the manufactory could realise this complex structure with sufficient time and tools, from steel or some other exotic material. For the comfort of my beloved sister, I would happily endure such expense and would commence work immediately if not for the boundary imposed by our limited choice of materials. Your suggestion of the polymerization of vinyl chloride is intriguing. Do keep me informed on what the chemists have to say for themselves. The structure proposed does mind me of those frames proposed to support the envelope of a rigid airship. Harriet is a handsome woman, who must exert little effort to maintain the attention of most gentlemen. However, with such a structure about her person, even those gentlemen for whom the allure of science and engineering holds more sway than that of a great beauty may regard Harriet’s with intrigue.
The frame you propose exhibits a very close fit, as we require. However, this presents to us a contradiction. A benefit induced harm has been introduced. The closer the fit, the more difficult it will become to don this mechanical attire. For example, how might Harriet’s foot pass through the narrow passage at the ankle? The device must be both loose-fitting and tight-fitting, separated in time. We will clearly require some mechanism to support the entry and exit of the invalid limb. This cage must come apart to permit access[8], or might be hinged down one side, to open and close like an undersea clam[9].
With the interface between woman and machine proposed we now observe a blank region in the centre of our illustration. We must turn to the question of those contradictions presented by the knee joint. For much of Harriet’s travels, a simple support to prevent the sway of her knee from one side to the other has been sufficient. Hence, my own skills at fabrication have been, up to the present day, sufficient to drive a solid bolt through the steel support of the brace to form a rudimentary hinge. However, Harriet’s prodigious mileage has taken its toll upon this poor joint, and therefore I suspect some mechanism to supply power to drive this knee may be demanded. The trouble begins when we consider the character of this driving mechanism. This hinge betwixt thigh and shin must exhibit two functions that oppose. This joint must not only rigidly support the injured knee, but must also bend to permit locomotion, or bend further still to adopt a seated position. I suspect that this motive force might be offered by a spiral torsion spring aligned with the knee joint. This spring should drive the knee straight and maintain Harriet into an upright position during those long hours at the operating table.
Uriah
[8] Separation principle 1. Segmentation. Divide the object into separate parts. Fragment the object into powders, grains, droplets, etc. Split the object into independent functions.
[9] Separation principle 15. Dynamics. Make a stationary object move or interchangeable. Make parts of an object move relative to one another. Optimise the conditions around each part of an object at each stage of operation.
17th August 1888
From: Archibald Jenkins, Oxford University.
To: Lord Uriah Chetworth, Cornwall.
Uriah,
A torsion spring will indeed provide some motive force to drive the knee. However, consider the action of such a spring upon the needs of a lady. As she lowers herself into her seat at the opera, or within a carriage, this tension would retard her ascent. A sufficiently taut spring able to support the leg straight for long periods may even prevent her from landing altogether. The knee must be driven straight but must also bend. When stood, Miss Harriet will require the strongest force to drive her leg straight. As she descends into a seated position, we would prefer this driving force to diminish, to reach zero upon landing and permit a comfortable seated position without compulsion to straighten the leg. Some mechanism to conveniently release this pressure upon the circumstance that we desire the leg to bend must be found. Conversely, the same mechanism must support the knee when a seated arrangement is no longer desired. The knee must not only support an upright position but also must not impede folding into a chair. Otherwise, we might as well splint Harriet’s knee permanently straight and be done with this puzzle, and I feel sure that from both our perspectives this solution will simply not be endured. I propose that a torsion spring will not serve our ends. Alternatively, to become both easily bent and not easily bent this modulation may be realised by pneumatic means[10]. A piston within a closed cylinder of pressurised air could oppose the bending of the knee, much as a torsional spring might. As the knee bends, the pressure within the cylinder will increasingly support the operation of the knee, much as the torsional spring might. However, with a pneumatic mechanism employed, pressure can be conveniently released from the chamber as desired, to allow Harriet to descend gracefully into a seated position. The split to be currently found in her skirts to provide access to her unusual affinity for a Colt single action army revolver should also offer a convenient means to access valves that might relieve the pressure behind the piston that bears her weight.
I have no doubt that Miss Chetworth can ascend from her seat unaided. However, in this circumstance, the mechanism I propose is now expended of pressure and can no longer offer support to the knee as Miss Harriet walks. To this end, it occurred to me that we could employ some small portion of Miss Harriet’s vigour to repressurise the system. Perhaps a small air pump might accompany this pneumatic support? As the leg bends, the pneumatic support acts as the piston compresses. As the leg straightens, the pressure is relieved within this supporting piston, to offer a convenient opportunity for a collateral but contrary pneumatic pump driven by the locomotive mechanism to force air into the primary supportive piston. Hence, as Harriet walks the force upon her knee stiffens to a suitable degree, moderated manually or by automatic relief valve.
A problem arises when we consider how the volume of such a mechanism might be mounted upon the patient. After all, those fellows of the medical faculty who specialise in the prosthetic replacement of limbs enjoy an advantage over ourselves, for their patients are typically missing a limb entirely. Hence, for these fellows, the supporting mechanism can reside within the body of the prosthetic. As Miss Harriet remains in full possession of her extremities, our device must remain outside the limb’s footprint, if you will excuse the pun. If I draw your attention to my sketches of this mechanism in the enclosed papers, I feel sure that you will immediately perceive the problem at hand.
Archie
Plate 3: A piston to the rear interferes with the back of the knee
Plate 4: A piston to the front is entirely unsuitable. The annotation is believed to be a later addition by Harriet Chetworth.
[10] Separation Principle 29. Pneumatics and Hydraulics. Replace solid objects with gasses or liquids. Inflate components or create cushions. Use a vacuum.
1st September 1888
From: Lord Uriah Chetworth, Cornwall.
To: Archibald Jenkins, Oxford University.
Archibald,
Your assessment of the patient is well made. Harriet is not so infirm that she cannot rise from a chair. She merely requires support for the long periods she might remain upon her feet. This need is by no means confined to her nursing duties, for, much like myself, Harriet is very much in possession of an affinity for those grand outdoor spaces. The inventory of family possessions includes a sprawling estate to be found in the wilds of Scotland. When my sisters and I were children the family would spend the summers upon this estate, amongst the hills and the lochs and the rolling landscapes of bracken and heather. Such highlands have always drawn Harriet, and the moment we arrived she would make for the hills and hike those mountain tops. Much to my mother’s disapproval, Harriet would on occasion remain out amongst the hills for the entire night, applying skills she had learned from local gamekeepers, fishermen, and even poachers, to live off the land, endure hardships, and return to the lodge both red-faced and hearty.
Harriet has quite the skill for languages and a facility for adopting those regional accents to be found in every corner of the world, with which she will entertain the other girls of the nursing mission after a long day on the wards. However, she spent such time in the highlands during her formative years that you will note, on occasion, particularly after a few whiskeys, that she will be unable to hide an edge of highland brogue adopted from long and close contact with those braw young gentlemen who manage the estate grounds and taught her much of survival in the highland wilds. Her forays into the mountains were a little curtailed by her subsequent injury at my hand, to compound my troubled conscience, but to double my desire to resolve the injury. Hence, a mechanism that stiffens to a firm support as she walks would suit Harriet’s need nicely.
However, good heavens, through only a moment’s observation of your illustrations I understand your point immediately, with no need for further explanation. If this pneumatic mechanism is placed forward of the leg, to circumvent the knee will require a prodigious length of mechanism. If this plumbing resides behind or alongside the leg, the connective mechanism thus folded will intersect with whatever surface Harriet may be sat upon. To resolve this conundrum, I am minded of Harriet’s frequent sojourn and my own challenge to our poor mother. Whatever she suggested, we would do the opposite[11] Charlotte and Silvia would do as they were told, taking after our mother as they do. However, both myself and Harriet would mercilessly drive our mother to distraction in our efforts to confound. Should she demand that we stay in, we would go out. What is constrained, must be free. What is long must be short. Up must be down, and in our current conundrum what is straight might become curved[12]? Might those pistons that not only drive the knee straight but also drive further air into this motive device become curved, to conform to the profile of the knee itself? Should the pistons become curved the pushrods required to maintain a link betwixt calf and thigh may only demand a short circuit around the joint, rather than the great span demanded from a more linear route? I have enquired with the gentlemen of the manufactory, who offer the enclosed drawing to illustrate my proposal
Uriah
Plate 5i: The gentlemen of the manufactory illustrate a curved piston.
Plate 5ii: The fabrication of curved pistons is clearly of concern.
Plate 6: From the records of Archibald Jenkins. A curved piston may remain within the boundaries of the knee joint.
[11] Separation principle 13. Do it in Reverse. Reverse a function. Implement the opposite action. Place an object the other way around or upside down or inside out. Start at the end, and work towards the start.
[12] Separation principle 14. Spheroidality. Curvature. Replace straight parts with curved parts. Replace motion in a straight line with rotation. Use rollers, or balls, or spirals, or domes. Use centrifugal force.
12th December 1888
From: Archibald Jenkins, Oxford University.
To: Miss Harriet Elizabeth Constantina Chetworth, Department of Topography & Statistics, Whitehall
Miss Harriet,
It was with both a great surprise and a profound pleasure in equal measure that I received you at my college. I had not anticipated your arrival and will admit to a great fluster to make myself presentable as you awaited my arrival in the quadrangle. I very much enjoyed our lunch together, to discuss arrangements for the knee brace, the construction of which is underway. I have had few opportunities during my time at Oxford to entertain a lady and must confess that I took the advice of the college porter, a most venerable and experienced gentleman who has taken great care of the residents for many decades, who directed me to the tearoom where we found a suitable repast.
I had absolutely no idea that you enjoy such success in the competitive sport of fencing, with sword in hand. I do hope that you prevailed at the Oxford Lady’s Open that you had travelled to the town to attend, and very much appreciate the short visit from you that I enjoyed as a result. I furthermore appreciate that the wear upon your knee may be exacerbated by this sportive exertion, to deny you that need for a sudden and explosive lunge to rapidly draw your weapon within range of your opponent. Our innovation, that we hope will serve you well, is to break our bond with cylinder and piston that reciprocate directly to and fro in a straight line, to in its stead offer a driving mechanism that will wrap conveniently about the structures of the knee. To offer support in your competitive lunge, I had but given this only a moment’s thought, and immediately felt confident that some means to momentarily pressurise the driving piston from a pre-charged reservoir of air would be entirely feasible, to provide a momentary boost.
Little did I know that you had a suggestion of your own and was surprised for a second time that day when you produced from beneath the table that held our tea an enormous Webley 0.45 inch calibre revolver. Your proposal was immediately clear, and I was thankful when you returned this revolver of astonishing size back to its place of carriage before the other patrons of the tea shop took note of your unexpected accessory. A giant of a pistol for a lady, I fear. However, upon the explanation of your need to defeat ferocious beasts that you may encounter in savanna, jungle or mountain demanded by your nursing duties I must take your word. Typically, we will always seek an elegant solution to problems posed, and to this end will seek resources within the problem space to serve our ends. I quite agree that an innovative solution to your problem might consider a connection between those pistons that might drive our mechanical knee, and the high-pressure gas generated by a blank round fired from this giant firearm. I fancy that with such a fearsome mechanism the pressure that may rush into the device might permit more than a sudden advance in a bout of fencing, but may in fact allow you to leap clear over your opponent, or other barrier that obstructs your progress. By integrating firearm with mechanical support, you might become our very own Springheeled Jack himself! Should the firearm be fully loaded with blank rounds, the bending of the leg might not only activate valves to relieve pressure to permit a reset of the knee’s action but also at the end of its travel might activate the trigger of this firearm, to drive yet more pressurised gas into the system and permit six fearsome lunges in a row until the firearm is expended. Unfortunately, to bear the stresses of such exertion, a fine steel structure may be demanded, rather than the elegant, lightweight novel materials that we had intended.
Uriah will no doubt appreciate the accommodation of this weapon into your brace, as your safety is clearly his primary concern. However, as you suggest, he might consider the application of this supplemental pressure to your fencing performance an unfair mechanical advantage, and we are both well aware of his enthusiasm for fair play. So, I shall indeed consider this embellishment to the original design as a confidence that shall remain between ourselves.
Archie
Plate 6: Jenkins modified the original design at the request of Harriet Chetworth.
Plate 7: Prior to the second world war, the only known example of this mechanism was stolen from its display at the Victoria and Albert Museum in London. No photographs or paintings of Harriet Chetworth are to be found in the public record, so journalists of the period had to rely upon artists impressions.