Chronometer and Chronograph, Two different words to say two different things, pretty normal, no?
Actually, it's two different functions that can apply to one and the same object. A chronometer is a high-precision timing device. It is a mechanism capable of keeping time, that is, of being precise. In accordance with defined criteria, it can be certified in Switzerland by the COSC, the Swiss Official Chronometer Control Organization. Whereas a chronograph, well, it's a timekeeping device with one or more independent hands that you can start, stop and reset, to measure intervals of time. A stopwatch will not give the time, it only allows measurements, while a chronograph watch will additionally indicate the time. And to sow confusion between the two definitions, between the two timekeeping tools, chronograph and chronometer, it is entirely possible to create a chronograph movement, i.e. one able to measure a time interval, and have it certified as a chronometer: that is to say, to ensure that the movement remains precisely within the scope defined by the COSC. And to add further to the frequent confusion between these two descriptions, we use the verb "to time" to define the operation of measuring an interval of time. So, it's simple: a chronograph is also used as a timing device! All rather confusing, and above all not a great help in telling the difference between the two. My grandfather, a watchmaker, Custom Luxury Watches, spent his life explaining and re-explaining it. As for chronometers, in today's era of atomic clocks that monitor each other, they have lost much of their previous importance. Who still uses a mechanical timepiece to get the exact, precise time? The word chronometer means, in terms of the COSC definition, only certain specific precision timepieces. And the required timekeeping criteria are now far from the type of precision offered by a low-cost alarm clock which is always correct to the exact second because it is tuned to a radio wave from Germany. So, let's all repeat together: Chronometer: a precision watch, and Chronograph: a watch for measuring intervals of time. And I haven't even started to make things complicated yet.
No history is ever completely tied down, which is proved by recent updates to the technical refinement of the chronograph. From the end of the 18th century onwards, some watches were fitted with a stoppable second hand. The first device to be called a "chronograph" was a mechanism for measuring short time intervals by depositing an ink droplet on a dial. Really! The "graph" part of the word "chronograph" is because it was effectively a way of writing down time. The reset function, which is essential for measuring time intervals effectively, did not appear until the middle of the 19th century. That was the starting point of the widespread use of the chronograph in sports, scientific research and especially industry. The pocket chronograph became the indispensable tool of technicians and engineers for understanding and improving industrial processes. Ask older workers what they thought of the famous "second-grabbers," the time-and-method specialists who measured production speeds in factories. "Time is money" and not just a little of it!
As they could measure short time intervals, chronographs soon came equipped with specific scales on the dial. The principle is simple: we measure the duration of a reference cycle via the chronograph hand; once stopped, it indicates a speed, a quantity, or some other value, per hour or less. For example, by measuring the time required to cover one kilometer, it is possible to work out an overall speed in kilometers per hour. Something that can be an educational game on the highway, to check out your speedometer. And then, equipment installed by the police can also be helpful, but maybe less entertaining and occasionally very expensive. The dial will show at the start of the scale the reference base used, for example "graduated for 1000 meters" or "base 1 mile". So, the chronograph can indicate measurements such as speed, the number of pieces produced, vital rhythms such as pulse rate or breathing, distance via a telemetric scale, stenographic speed, and so on