"The Glass Bathyscaphe" by Alan Macfarlane and Gerry Martin

Perhaps I missed it. I don't remember reading anything about a glass bathyscaphe (a power underwater craft made mainly of glass). I checked the index: no bathyscaphe is mentioned. The title seems to refer only to the illustration on the cover. The book is focused entirely on its subtitle: 'How Glass Changed the World'.

Glass-making has been around for a long time in Eurasia but its early use was almost entirely ornamental, using opaque, coloured glass. Thin transparent glass requires glass-blowing techniques, developed “somewhere in Syria or Iraq” in c100 BCE (Ch 2). The authors carefully distinguish various uses of glass as ornaments, vessels, windows and mirrors and suggest that it was the fact that glass windows were so useful in the cold climates of northern Europe (enabling people to work indoors; there were glass windows in Britain during the Roamn occupation)  that led to the emphasis on transparent glass which is so useful for the key scientific instruments that were essential for the scientific revolution (not just see-through (and heat-proof and inert) reaction vessels for chemistry but also thermometers, barometers, vacuum-pumps, telescopes and microscopes, not to mention lanterns, sextants and chronometers to assist sea travel and even light bulbs.

As well as science, the authors consider the effect of glass on art, particularly the development of perspective, which they suggest, with evidence from contemporary sources, was facilitated by the use of mirrors. They also suggest that windows encouraged paintings because both are framed and show how some early renaissance artists used panes of glass as drawing aids.

They further hypothesise that the western European cult of individuality was encouraged by glass mirrors; they suggest the rise of autobiographies correlates with the rise of glass mirrors.

They even suggest that the reason the scientific revolution did not take place in East Asia was because they never developed spectacles. The book theorises that this is because they have much higher rates of myopia than in western Europe. They hypothesise that this is because (a) the traditional rice and vegetable diet contains too little vitamin A and (b) they have a strong literary tradition, with young children forced to learn a large number of literary texts from a very early age; the resultant eye strain causes myopia. But myopia in young children is an eye defect among the relatively economically powerless so there was no need for spectacles (and a short-sighted person can still read by putting their face very close to the page); furthermore the gradual increase in long-sightedness as people age would mean that older people didn’t need spectacles. In contrast, the eye defect in the west was predominantly long-sightedness which makes it nearly impossible to read and this stimulated the demand for spectacles.

This is therefore an ambitious work! The arguments are persuasive although I was rarely convinced; perhaps a smaller focus and a greater depth of evidence would have sealed the deal. Nevertheless, it was an entertaining read. But where was the bathyscaphe?

Selected quotes:

• “Discovery sometimes comes after a first rough set of guesses has begun to seem plausible enough to justify detailed examination.” (Ch 1)
• “A world of continuous investigation and assessment of nature and social relations, has many enemies. Most human beings prefer certainty and order above all else. Most innovations and change threaten such orderliness. In particular, new ideas can be subversive and dangerous. Much of history shows the tendency of thought systems to close down, solidify, and put up increasing barriers to disturbance. ... One aspect of this is what might be termed roughly the tendency towards inquisitorial thought. ... ‘Heresies’ are now rooted out; challenges to the thought system are seen as threats to the social and political order. The thought police are active, but do not need to be called in because of self-emasculation by individuals under all sorts of pressures, including those of loved ones. ... Whether it is the Jesuits or the Mandarins or the Mullahs, a strict enforcement of the notion the certain ideas must not be challenged becomes widespread. It is more important to learn the old truths and reinterpret them than to learn new ones.” (Ch 3) 
• “This curiosity, the impetus to test and speculate, the sense that there were expanding horizons of knowledge, that not all was known and there were new worlds to be discovered, were boosted by the rapidly expanding wealth and technology of the period. The new burst of power through the intensive exploitation of wind, water and animals, the growth of trade and cities, and the expansion of Christianity ... encouraged experimentation.” (Ch 3)
• “Glass shifts authority from the word, from the ear and the mind and writing, to external visual evidence. The authority of elders is challenged; the test is the individual eye and the authority of the doubt-filled and sceptical individual.” (Ch 4)
• “At the two ends of Eurasia very different cosmologies and ideologies developed ... at one end of the continent a glass civilisation emerged, and at the other a pottery and paper one.” (Ch 6)
• “It is one of the ironies of life that just as they reach the peak of knowledge, in their late forties and fifties, many people find it impossible to continue reading without glasses.” (Ch 8)
• “The invention of spectacles in creased the intellectual life of professional workers by fifteen years or more. ... The revival of learning from the fourteenth century onwards may well be connected to this. ... The active life of skilled craftsmen, often engaged in very detailed close work, was also almost doubled.” (Ch 8)

July 2022; 213 pages

This review was written by the author of Motherdarling  and The Kids of God