Natural Philosophy Collection

Scientific instruments used to be built for people; today they are manufactured for businesses, institutions and laboratories. A scientific instrument is more than just a measuring tool; it is an artefact of the society that created it, reflecting not only the technology of that society but some of its culture and customs. Listen to the innovative nineteenth century engineer Fleeming Jenkin, writing in a letter to his fiancée. "I have a nice office to sit in, with a fire to myself, and bright brass scientific instruments all round me, and books to read and experiments to make, and enjoy myself amazingly". The scientific instrument of a hundred years ago had a decorative and aesthetic role that it seldom does today.

Most scientific apparatus has a scale dictated by the size of people, and we haven't changed much over the centuries. It may now be easy to make a thermometer smaller than the size of a pinhead but the electrical wires from it are connected to a box with buttons or knobs that your fingers can operate and a display with digits large enough to read at arm's length. The digital thermometer you buy over the counter is, if anything, a little larger than its glass predecessor.

Even in simple devices, today's electronic boxes are full of hidden complexity. Compare them with the simple glass-tube mercury thermometer, which has no hidden parts. With the mercury thermometer, you see what you have, and its operation is readily analysed and understood. Today's electronic boxes are likely to have autozero, linearity correction, internal calibration and other user-friendly features of genuine value. Many deliver more accurate readings than their predecessors but few users know what the electronics does or, even, the basic phenomenon used by the sensor. They are, in all senses of the word, opaque.

Individual components at the beginning of the 20th century were large. A few examples are on display. Components, particularly electronic components used in measuring instruments, have shrunk progressively during the century. PentiumTM chips that provide the computational power of PC's at the end of the twentieth century in about the size of a very large postage stamp have nearly 10 million transistors, interconnected with wires some 0.2 microns wide. [A typical human hair is 50 microns wide]. Even mechanical components such as gearwheels and pumps can now be made so small you need a microscope to examine their detail. Many modern parts are too small to be physically assembled and installed by human fingers.

Each piece of apparatus at the beginning of the 20th century usually had a single and quite restricted function. As the century progressed and instruments were built that offered a greater range of facilities within a box of much the same size, so the instruments acquired more knobs and controls. In the last decade or so, the "intelligent" instrument has arrived, now with very few controls. The simple digital multimeter is a common example. Along with simplicity of controls has come simplicity, some would say monotony, of display. Think of the huge variety of style and ornament that can be found among the circular dials of clocks, compasses, radios and innumerable 'meters'. Now, each of these displays is often reduced to a panel showing a simple line of digits representing the time, the orientation, the frequency or whatever other property the meter measures. The digital revolution has swept through the field of physical instruments over the past decade, leaving little unchanged. The result is that modern instruments are more accurate and more functional. They have brought with them, though, a new aesthetic which, like modern music and poetry, will take time to develop and receive general appreciation.

Scientific instruments have exhibited the changing use of materials through the twentieth century no less than other more widely spread products of industry. Indeed, always wishing to be 'up with the times', they have been in the forefront of change. Most of our examples are from the field of electrical instruments. Dovetailed and varnished wood soon gave way to painted metal boxes. In many cases, this change was dictated by electronic considerations as well as the economics of pressed steel and extruded aluminium. Metal boxes contain the electrical interference generated by switching circuitry and high-frequency signals that would have escaped from a wooden box. We see over the century the rising use of synthetic materials, like celluloid, bakelite and tufnol. Today, metal has not only lost out to moulded plastic but has lost out because of fundamental changes in the measuring process. The surveyor's weighty precision theodolite has given way to the laser measurer and the electronics of Global Position measurement Systems (GPS). Weighty, metal standard length measuring equipment in the laboratory has been replaced by precision laser substandards. In many instruments, the only metal left is the wires connecting the electrical components. In years to come these too may succumb to the rise of optical signalling and signal processing. There is every sign that scientific instruments are still a rapidly evolving area of human creativity.

Analogue Computer mid twentieth century. The ultimate experience in electronic control. Sound mathematical arguments show that electrical circuits can be built to mimic the behaviour of mechanical systems, heat flow, fluid flow and many other forms of physical behaviour. The analogue computer used modular electronic circuits that could be put together according to the requirements of the particular problem to be solved. A new problem required building a new, complex circuit.