In this blog post, we will examine the significance of Dalén’s invention at the time and why it has been underappreciated over the years.
The question “Who is the greatest Nobel Prize winner in physics?” always provides us with an interesting topic of discussion. If someone asked you this question, who would you choose? Niels Bohr, who opened the door to quantum mechanics? Heisenberg, who discovered the uncertainty principle? Einstein, considered one of the greatest physicists of all time? Once you have thought about your answer, let’s consider this question. What is the worst and most disappointing Nobel Prize in Physics ever? Niels Gustaf Dalén’s invention of an automatic regulator for gas reservoirs used in lighthouses, which won the Nobel Prize in Physics in 1912, ranks first in various surveys asking for the worst Nobel Prize in Physics ever. His invention, an “automatic regulator for gas reservoirs for lighthouses,” has become obsolete in modern times and is considered a disappointing achievement. However, when evaluating a person’s achievements, we should not judge them solely by modern standards. We must consider what problems society was facing when he conducted his research (or invention), what results his achievements brought about, and how they were evaluated at the time.
In the early 20th century, the shipping industry (long-distance trade) grew explosively thanks to the colonial rule of the great powers. In an era without GPS, lighthouses were the only thing that sailors could rely on during nighttime voyages. Every year, thousands of people died trying to dock at ports at night. At the beginning of the 20th century, the number of lighthouses in Sweden increased nearly tenfold in just ten years, which gives us an idea of how important lighthouses were at the time. Under these circumstances, securing high-performance lighthouses was a matter of great importance to all countries and those engaged in trade. The new acetylene manufacturing method developed in 1895 was enough to excite them. Acetylene burns with a very bright white light, making it ideal for use in lighthouses, and the new manufacturing method enabled mass production of acetylene. However, several fatal flaws were discovered during the practical application of acetylene, the most serious of which was its volatility and explosiveness under atmospheric pressure, which made it difficult to handle. To overcome the dangers of acetylene, Nils Gustaf developed a porous material called “Agamassan” and announced a storage method that involved dissolving acetylene in acetone and storing it in Agamassan. This material and storage method, which dramatically improved the safety of acetylene, are still used today for the storage and transportation of acetylene.
Although the safety of acetylene had been resolved, Nils Gustaf’s “Aga” faced another problem. Lighthouses needed to be able to emit intermittent light to distinguish themselves from other lighthouses or other lights. The conventional method of creating flashing lights was to cover the lamp with a screen or rotate the lamp, but this method was too inefficient for acetylene lamps, which were more expensive than conventional lamps. Dahlén solved the problem of acetylene lamps by devising a new device for opening and closing the gas pipe. Then, in 1907, he developed the “sun valve,” which was the culmination of his achievements. The sun valve consisted of several black rods inside a glass tube, as shown in the figure below. When sunlight heated the black rods, they expanded and closed the valve, and when the sunlight disappeared, the rods contracted and the valve reopened. It was a kind of gas valve with a solar sensor. His solar valve reduced fuel consumption in lighthouses by 94%, and his invention made it possible to install lighthouses and buoys in locations that were previously difficult to access for maintenance.
His successive achievements established the new “Dalen lantern” in maritime countries around the world, and its value was beyond imagination. Previously, it cost 200,000 kronor to build a lighthouse on the coast and 25,000 kronor per year to maintain it, but after his invention, it cost only 9,000 kronor to install and a mere 60 kronor per year to maintain. Considering that the total expenditure of the Swedish central government in 1910 was only 250 million kronor, one can imagine how much money the Dahlen lighthouse saved.
However, Dalen’s revolutionary “Dalen lamp” also faded into history with the spread of electricity. As electricity became available to the general public, gas-powered lighthouses fell out of use, and Dalen lamps, which were inferior to electric lamps in both price and performance, gradually disappeared.
His invention is often compared to other Nobel Prizes in Physics. It is true that his achievements are not as widely recognized today as those of Van der Waals, who won the Nobel Prize in 1910 for his equations of state for gases and liquids, or Wien, who won the Nobel Prize in 1911 for his law of thermal radiation. However, given the circumstances of the time, his achievements in improving lighthouses and saving many lives were worthy of praise. The stingy evaluation of Dalen’s award may be due to the fact that he was the last inventor to receive the Nobel Prize in Physics due to changes in the evaluation criteria for the Nobel Prize in Physics.
