It is quite common that people get asked what they think is the most import development in technology or the most significant technological invention in human history. Apart from the ubiquitous wheel, which is almost certainly the most common answer, unless they are historians, they will almost always name something comparatively modern and usually big and impressive–the steam engine, the automobile, the airplane, the computer or whatever. However, having been at one time in my life, for a number of years, an archaeologist, I am very much aware of the massive impact that seemingly everyday things had on the development of human society–the most obvious is cooking with fire, but also making, ceramics, bricks, glass, simple tools, and many other things many of them seemingly small and insignificant. In response to a fascinating blog post by Rachel Laudan on the uses to which gourds were put in the history of cooking, I once wrote a blog post on the significance of the invention of the sewing needle.
This being the case, I couldn’t resist when I came across reviews of Roma Agrawal’s book Nuts & Bolts and bought a copy, which I read with growing enthusiasm and delight. I couldn’t resist because the full title is Nuts & Bolts: Seven Small Inventions That Changed the World (in a Big Way).[1]
Roma Agrawal is not a historian but a structural engineer, a graduate of Oxford University, BA physics, and Imperial college, MA Structural engineering, who has worked on major engineering project, including the Shard in London. In her book she brings an engineer’s eyes to a popular historical view of the nail, the wheel, the spring, the magnet, the lens, string, and the pump. Outlining not only their origins, their evolution, the multiple forms they have taken and the multiple uses to which they have been put but also giving a soft scientific and engineering explanation of how they work in terms of forces and resistance.
From the outset this book is wonderfully written and a delight to read. The world’s textbook writers could learn a lesson or two from Agrawal on how to hold a reader’s interest and entertain them whilst at the same time educating them. She makes it seem very easy.
She starts with the nail, a very simple, small, seemingly insignificant everyday object that most people wouldn’t even think of when asked to list important historical invention. However, the nail is and has been a very important element in building projects of all sizes throughout the world for millennia. She traces its origins, its developments, and its very important transition from being hand forged to machine made. She explains how the force of friction enables nails to hold things together. However, she doesn’t just deal with nails in this chapter but with screws, rivets, and nuts and bolts, which as she explains are all basically evolved forms of the humble nail. In this direction the mental leap that most surprised me is that the piles–wood, metal, concrete–driven into the ground to support building are in reality just very big nails.
After the nail, Agrawal turns to that perennial favourite greatest invention, the wheel. We of course get the wheel enabling transport but more significantly she takes her readers on a whirlwind tour of many of the other places where wheel can be found fulfilling an important function. We have the potter’s wheel, cog wheels and gear wheels, the invention of the bicycle and the invention of the gyroscope. She includes a fascinating section on Josephine Cochran’s invention of the dishwasher. One facet of Agrawal’s narratives is that where possible she draws attention to the contributions made by women to the history of technology. She takes us through the evolution of better wheels from the simple solid plank wheel down to the sophisticated spoked wheels of modern bicycles and closes by stating, “Human progress and the reincarnations of the wheel and axel are intricately intertwined. And that’s why we should absolutely continue to reinvent the wheel.”
Our next small invention is the humble spring, which doesn’t immediately spring to mind when asked about the greatest inventions. (I’ll let myself out!) One revelation that totally blew my mind when I first read it, is that the bow, as in bow and arrow, is a spring! If you want to know why the elaborately curved Mongolian bow is superior to the European longbow this is the place to go. Moving on via springs in guns Agrawal land at a device that lives from its springs the mechanical clock. Here we meet another aspect of Agrawal’s approach, hands on. The opening paragraphs of the nail section found her hand forging nails in a smithy, we now find in the workshop of Dr Rebecca Struthers, independent watchmaker and horologist. Struthers put out her own book Hands of Time: A Watchmaker’s History of Time (Hodder & Stoughton) in 2023. The lady engineer and the lady watchmaker take the reader through the history of the clock and the central role that springs came to play in their construction. John Harrison, of course, gets a nod on route. Fascinatingly the structural engineer introduces her readers to building, suspended on springs to protect them from earthquakes or to shield them from external vibrations.
Our interest is now directed to the magnet, where it is not long before we get briefly introduced Dr William Gilbert and his De Magnete but we don’t linger, quickly progressing to the development in magnets and their materials now that magnetism had been established as a science. Having sketched the developed the modern magnet we get introduced to the electric telegraph, a massive communications revolution, that depended on magnets. The electric telegraph was superceded by the telephone another communications device dependent on the magnet. This capital argues for the magnet as the driver of modernity with the television following on the heels of the telegraph and telephone. Here Agrawal pulls another rabbit out of her hat, ignoring the western developers in favour of the story Takayanagi Kenjiro the independent Japanese inventor of the television. The section closes with the story of LEDs.
Up till now, whilst reading, I was really enjoying Agrawal’s fascinating and stimulating book and then I ran into her section on the lens, and soon wished I hadn’t. Readers of this blog will know that the history of optics is one of my special areas of study and I’m sorry but Agrawal’s story of the lens is a trainwreck! I’ll move on for now but return to the lens later.
As opposed to the chapter on the lens, the chapter on string is a delight. Agrawal opens with the steel cables that hold up suspension bridges, which is not what one normally thinks about when somebody uses the word string. However, as she points out the cables on smaller suspensions bridges, such as the one that was one of he first engineering projects, are twisted together out of steel fibres in exactly the same way as string is made by twisting together plant fibres. The heavier ones are made with a slightly different process but are also basically string. She then moves on to sewing and the sawing needle, sewing thread being, of course another form of string. Moving on we have cloth which is usually woven or knitted string. String has truly played a major roll in human history. The chapter closes with a discourse on music made with string instruments and instead of the violins or guitars, one might expect we get a fascinating detailed description on the tanpura, the drone instrument in Indian music, and how the strings are manipulated to produce the vibrating, droning sound.
The final chapter is devoted to the pump, which Agrawal defines as a way of raising water to a higher level. After a brief sketch of the history of the water lifting devices, she turns to a description of the most fascinating of all pumps, the human heart. The heart is a small pump with an incredible performance. However, Agrawal is not deviating from engineering to biology but the description of the heart is used as an introduction to the story of the development of the heart-lung machine, a truly fascinating story of a piece of medical engineering history. After this excurse into the medical discipline we follow Agrawal into the equally fascinating story of the development of the breast milk pump, which Agrawal was led to through her own problems with breast feeding.
We return to the lens. This starts, as much of the book, with a personal anecdote about the conception of Agrawal’s daughter, which was by artificial insemination and a description of the microscope developed to study the insemination of ova. This is one of several personal stories in the book that illustrates Agrawal’s interest in the topic under discussion. Having introduced the lens through the microscope, we now move back to the origins and history of the lens, here she goes off the rails. She accepts that the so-called Nimrud lenses (7thcentury BCE) are lenses and not simply ground and polished pieces of lens shaped crystal, for which there is simply no proof whatsoever. I think they are more probably decorative stones.
She now moves on to the Greeks and writes the following:
The Greeks laid down some basic rules of how light reflects off mirrors and even bends through lenses.
The Greeks did indeed study the basics of refraction but those studies had almost nothing to do with lenses. The most extensive study of refraction was by Ptolemaeus, who was concerned with atmospheric refraction in astronomy and most important failed to determine the sine law of refraction. She continues:
Having quickly rubbished Greek theories of optics without going into detail we arrive at Ibn al-Haytham (b. 965 BCE). After a biographical sketch she makes the claim that “he finally explained correctly how sight works.” Although Ibn al-Haytham made great progress towards a correct explanation of how sight works, it is by no means completely correct and above all most of the elements he uses in his model are taken from the Greek sources that she doesn’t present. She then presents one of al-Haytham’s experiments claiming that it proves his theories, which it doesn’t. We then get the extraordinary statement:
Ibn al-Haytham’s work related to optics was groundbreaking for many reasons. For the first time, someone suggested correctly, that light exists independently of vision.
Sorry, but this is pure and utter garbage!
He also said that light travels in rays along straight lines, and these rays are not modified by other rays that cross their path.
This was already known to the Greeks.
For the first time, he conducted a scientific study of images formed by lenses.
Ibn al-Haytham did not conduct a scientific study of images formed by lenses. He made some minor comments on the images formed by spherical lenses.
We then get the classic:
In another interesting link, physicist Jim Al-Khalili writes that Ibn al-Haytham’s discussion on perspective-which was translated into Italian in the fourteenth century-enabled Renaissance artists to create the illusion of three-dimensional depth in their work.
This illustrates a major problem in her work on al-Haytham, she uses the highly hagiographic and historically inaccurate work of Al-Khalili as her source, rather than the historically accurate, in depth studies of David C. Lindberg, A. Mark Smith, and A. I. Sabre.
As far as the development of linear perspective during the Renaissance is concerned, the geometry of linear perspective is the optical geometry of Euclid, which is in no way dependent on anything al-Haytham wrote. Of the early developers of linear perspective Lorenzo Ghiberti (1378–1455) indeed quotes al-Haytham. However, we know nothing about the sources which inspired Filippo Brunelleschi (1377–1446) to carry out his famous demonstration of linear perspective. Finally, Mark Smith thinks that Leon Battista Alberti (1404–1472), who wrote and published the first explanation of linear perspective in his Della Pittura (1435)/De Pictura (1436) did not reference optical literature to write his book but that it was based on his work recording the architectural ruins in Rome using a plane table. More importantly, Alberti states clearly in his book that for linear perspective it is irrelevant whether one holds an extramission theory of optics, Euclid, or an intromission one, al-Haytham.
We then get the claim that that Ibn al-Haytham “laid the foundation of what we now describe as scientific method.” As al-Haytham’s experimental programme is an extended copy of that of Ptolemaeus’ programme this claim is simply refuted.
Following an explanation of how lenses work, we get a horrible piece of ahistorical garbage:
The science of optics advanced significantly in the Islamic empires, but the practical applications of lenses remained largely limited to burning glasses and simple magnification. Centuries later, when the Islamic Golden Age of science [my emphasis] began to dim in the Middle East, and as light began to break through the Dark Ages in the West, [my emphasis] Europe’s Renaissance thinkers built on the work of their medieval counterparts to truly harness the superpower of lenses.
The concept of the Islamic Golden Age of science is, today, increasingly viewed with scepticism by historians as it is particularly difficult to define just when it was supposed to have ended. The term Dark Ages, however, is not just viewed with scepticism but has been totally banned from the vocabulary of serious historical discussion.
Having written this paragraph, Agrawal then dives straight into the invention of the microscope, strangely making here no mention of either the invention of eyeglasses (spectacles) or the telescope. This is particularly bizarre as a couple of pages earlier she had written, “ He [Ibn al-Haytham] laid the foundations for scientists after him – including Newton, who published his work 700 years later – to not only study and explain light even further, but also to engineer spectacles, microscopes, telescopes, cameras, and more.” Note Newton gets a name check but a whole list of other significant contributors to the history of optics, Kepler for example, don’t. Without the invention of spectacles, no industry of lens making would have developed, and without spectacles no telescope, and without the telescope no microscope!
Interestingly, the earliest date for the end of the so-called Islamic Golden Age of science is the fall of Baghdad at the hand of the Mongols in 1258, which almost coincides with the invention of spectacles in Northern Italy, which by the way, was in no way connected to the optical theories of Ibn al-Haytham.
We get a few lines on Robert Hooke and his Micrographia before she writes the following:
No doubt inspired by Hooke’s work, a Dutch shopkeeper with little formal education decided to look closer, leading him to seeing many things that humans had never seen before.
The Dutch shopkeeper is, of course Antony Leeuwenhoek, who was actually quite a bit more than just a shop keeper. There is actually no evidence that Leeuwenhoek was inspired by Hooke. This is a purely speculative theory proposed by Brian J. Ford, who is the source that Agrawal uses for he comments on Leeuwenhoek.
There follows an account of Leeuwenhoek’s single lens microscopes which ends with the following:
Holding the microscope up to his eye, he could peer through his handmade lenses, some of which could magnify objects by an astonishing 266 times. To put this in perspective, the microscopes with two lenses invented in the late sixteenth century by the Dutch father and son team, Hans and Zacharias Janssen[my emphasis], could only magnify up to a maximum of ten times, because of the limited quality of the lenses and blurring effects first studied by Ibn al-Haytham.
The claim that Hans and Zacharias Janssen invented the microscope in the sixteenth century was very dubious at the best when it was first presented, apart from anything else Zacharias Janssen would have been only four-years-old at the time given in the story. However, modern research by Huib Zuidervaaart, has shown that Zacharias Janssen, who is also credited with the invention of the telescope, had nothing whatsoever to do with optics before 1616.
We don’t actually know who invented the microscope but it is assumed that several early telescope makers and user, such as Galileo, looked through their Dutch or Galilean telescopes the wrong way round and realised that it functioned as a microscope. Several people in Galileo’s circle in the Accademia dei Lincei used such Galilean microscopes and it was Giovanni Faber of the Lincei, who gave the instrument its name. The first use of a Keplerian telescope, with two convex lenses, is credited to Cornelis Drebbel in 1619.
We then get an account of Leeuwenhoek’s discoveries culminating in his discovery of sperm. Agrawal writes:
Combined with the theory that all female animals have eggs, which also made its appearance in the mid-1670s…
This theory originated with William Harvey in his De Generatione, Ex ovo omnia – All things come from an egg, in 1651.
The rest of the chapter deals with the development of the microscope and its use in artificial insemination followed by a long section on the history of the history of the camera, both more or less acceptable.
Of course, the series of historical errors in this chapters leads on to speculate if the history in the other chapters is accurate. Unlike this chapter the others are not my speciality but as far as I could ascertain they are historically acceptable.
The book has neither foot nor endnotes. There are lists of the experts consulted for each chapter and also a separate extensive bibliography of sources for each. There is also a useful index. The book has occasional black and white illustrations many of which are had drawn, one assumes by the author. Despite my complaints about the chapter on the lens, I recommend Roma Agrawal’s book, which is despite the flaws mentioned above an excellent read.
[1] Roma Agrawal, Nuts & Bolts: Seven Small Inventions That Changed the World (in a Big Way), Hodder & Stoughton, London, 2023.