Julius Robert von Mayer (1814-1878)

The Unsung Hero who Preceded Energy Conservation Notion

Julius Robert von Mayer [Image: allposters.co.uk]

The term ‘energy’ has had a solid understanding at present, contrary to what scientists living in the early 19th century experienced. Scientists at that time had contacts with a variety of phenomenon such as mechanics, electrical, chemistry and magnet. Nonetheless, there was no exact definition and understanding upon what we call nowadayas ‘energy’.

Alessandro Volta, for example, in 1800 discovered electrical cells which was able to generate electricity from chemical phenomenon. 22 years later, Thomas Seebeck showed that the joint of 2 metal plates could produce electricity while being heated. Jean Peltier, 12 years later, demonstrated that electricity could result in cooling effects.

Once a phenomenon undergoes a change of form resulting another one, then a number of measures in the former is qualitatively replaced by the same amount in the later. The size, the amount of the replaced-measure is invariable; during the conversion process, the total amount is constant. Towards the end of 18th century, this conservation principle had been very popular. However, it left one big question: “Among those changes, what measure actually left constant?”

Alessandro Volta, generated electricity from chemical phenomenon. [Image: http://www.time.com

Well, one of the first scientists struggled with that conceptual speculation was Julius Robert von Mayer. He is a German who was educated as a physician. If life was to follow linear rule, then Robert von Mayer should be a physician. But, history provides us with the facts that Robert von Mayer has his glorious name engraved at the heart of physicists. He joint medical school at the University of Tübingen. Finally managed to graduate as a doctor, Robert von Mayer decided to be a surgeon on a Dutch ship instead of opening a practice in his town, Heilbronn. Then, he arrived in the land of Java.

His intellectual adventures actually began from one port located in East Java. Around 1840, he examined the blood of sailors and discovered that the blood coming out from veins was bright-red. He had only one assumption: the color shows the low rate of metabolic oxidation. According to him, in warm temperate regions, the oxidation rate is lessened. Mayer was so happy to what he found which was a new fact in medical field at that time: i.e., metabolic oxidation is a physiological conversion process.

Mayer went home to Heilbron in 1841 and started writing scientific papers. He said, “all things will change, which could not occur without the presence of what we may call as force,” and “we could generate phenomenon from the very basic force.”

The word ‘force’ used by Mayer is very different from what we embrace today. 19th physicists used the expression in two occasions:

  1. while having contact with Newtonian concept, especially when explained attraction or repulsion,
  2. while explaining what we call as energy.

In all of Mayer’s writing, the word ‘force’ is intended as ‘energy’. Thus, his scientific papers act as the very first referral of energy conservation principle.

Justus von Liebig, the editor of Annalen der Chemie und Pharmacie. [Image: http://www.uh.edu

However, his scientific papers were perpetually rejected. He sent to the Annalen der Physik und Chemie of Johann Poggendorf, but was rebuffed. Armed with perseverance and because of the aid of his friend, Carl Baur, he finally managed to publish his toughts in the Annalen der Chemie und Pharmacie of Justus von Liebig in 1842. In the journal, he demonstrated calculations based on laboratory observations, i.e. that the heat required to raise gas temperature in isobaric (constant-pressure process) is much higher than isochoric (constant-volume process).

The difference in the system, he said, resulted in the different amount of heat converted into work. His calculations showed that 1 kcal of heat capable of lifting 1 kg load as high as 366 m. This is what we call mechanical value of heat. In fact, Mayer miscalculated which then corrected by Victor Regnault in 1850. James Joule conducted his own experiments and found the mechanical value of heat 425 kg.m/kcal in 1843. Using Mayer’s method, Regnault discovered the value of 426 kg.m/kcal.

Henri Victor Regnault. [Image: http://www.nndb.com

Mayer kept doing experiments. In his scientific paper published in 1845, which was repeatedly rebuffed also, Mayer penetrated further into the theory of energy conservation. He wrote, “In reality, there is only one single force which cyclically experiences change of form throguh the exchange between inanimate objects and organisms. Anything in the past or future will not materialize without the variances of this force.”

The deaths of his three children around 1846-1848 shook his mental stability. In 1850 he was depressed and suicidal. He was then put in a mental hospital, and just out of there in 1853. Then Mayer returned to Heilbronn and open medical practice. Nearly 10 years he stayed away from the scientific world while at the same time thermodynamics were being developed rapidly without mentioning his name at all. Liebig and Poggendorf in the year of 1858 even reported that Mayer had died in a mental hospital. However, thanks to John Tyndall, who was also associate of Michael Faraday. It was Tyndall that made Mayer widely known.

John Tyndall. [Image: communicatescience.eu]

Tyndall was about to prepare a series of lecture on heat. He wrote to Helmholtz and Clausius, talking about Mayer’s ideas. Clausius stated that Mayer’s writing were unimportant and promised to sent Tyndall a copy of Mayer’s works. However, in his second letter to Tyndall, Clausius said, “I draw my remarks which say that Mayer’s works are unimportant; I admire the beauty and the truth of his thought.” It was not only Clausius that said so, but also Helmholtz, who stated that Mayer was the very first scientist who understand the concepts and principles of energy conservation.

Tyndall then discussed heat in his lecture, and outlined the Mayer’s role upon energy conversion and energy conservation by saying, “What I explain to you all is taken from the work of a German physicist named Julius Robert von Mayer.” He also said that Mayer was even superior to James Joule: “Joule published a scientific paper entitled On the Mechanical Value of Heat in 1843, but Mayer had done the similar calculation in 1842.”

Mayer, who had lived in his ‘chateau’, suddenly became the focus of scientific community. Tyndall and his friends argued with Joule’s stronghold in a number of media such as Philosophical Magazine. Tyndall asked Mayer to speak. Finally, Mayer’s scientific papers were published in the magazine. The recognition upon Mayer’s works came too late for a scientist who had experienced perpetual rebuffed, denial, mental fatigue and death-reporting by his own fellow scientists. Several years before his death, Royal Society awarded him Copley Medal for his work in the mechanical value of heat. [SM]