Question: In 1917, Einstein's research was peaking in what area?
About the article "Albert Einstein", section "Modern quantum theory".

Candidate passages:
Einstein's unsuccessful investigations are in addition to his life's work.
Einstein conducted other investigations that were unsuccessful and abandoned.
These pertain to force, superconductivity, gravitational waves, and other research. 
Lorentz was one of few scientists who supported Einstein's search for general relativity from the beginning – he wrote several research papers and discussed with Einstein personally and by letter.
For instance, he attempted to combine Einstein's formalism with Hamilton's principle (1915),and to reformulate it in a coordinate-free way (1916).
Lorentz wrote in 1919: 
During this period at UCL, Rankine worked under the Irish physicist Frederick Thomas Trouton.
In 1908, he and Trouton carried out what become known as the Trouton–Rankine experiment.
This experiment was among a number being carried out at the time, and was intended as a test of aether theory and Einstein's special relativity, with Trouton and Rankine's null result providing support for the latter theory.
Two years later, in 1910, Rankine obtained his D. Sc in Physics (awarded by the University of London).
A further two years after that, in 1912, he was elected a fellow of University College.
His research in this period was on the viscosity of gases, and he invented a viscosimeter (the "Rankine viscosimeter"), enabling him to carry out experimental determinations of the "Sutherland constant" (described by William Sutherland).
The aim of this work was to produce estimates of the size and shape of gas molecules, and Rankine's results in this area were published between 1910 and 1926.
While at UCL, Rankine also served twice as President of 'The Chemical and Physical Society' (ChemPhysSoc), the students' society of the chemistry and physics departments, doing so in the years 1910-11 and 1915-16.
During World War I, many scientists were seconded to carry out wartime research for the government.
Rankine's wartime research took place in 1917 and 1918, and he worked under recently appointed UCL professor William Henry Bragg and British-born Canadian physicist Arthur Stewart Eve.
Rankine worked first at Aberdour on the Firth of Forth in Scotland, then at the Harwich research station, both as part of work by the Admiralty Research Laboratory.
His final posting was as Director of the research station at Kingswear.
Rankine's work during this period included developing submarine detection technology.
Rankine's research during and immediately after the war also looked at ways to achieve the optical transmission of sound, a problem being worked on by other scientists and engineers in several countries.
The device was similar to the photophone constructed by US inventor Alexander Graham Bell in the 1880s, and the system being developed by the Polish engineer Joseph Tykociński-Tykociner from 1918.
Rankine's work in this area was mentioned in "Popular Science" in 1922, and has been described as an "effective technique for the transmission of speech by sunlight".
For his government research work during World War I, Rankine was made an OBE in 1919. 
General relativity has a number of physical consequences.
Some follow directly from the theory's axioms, whereas others have become clear only in the course of the ninety years of research that followed Einstein's initial publication. 
We have to obtain a suitable tensor to describe the geometry of space in the presence of an energy field.
Einstein proposed this equation in 1917, written as:formula_3(const) is what will become Einstein's constant.
We will take the cosmological constant Λ equal to zero (one of the requirements of the properties of the gravitational equations is that they reduce to the free-space field equations when the density of energy in space "Tαγ" is zero, therefore that the cosmological constant λ appearing in this equation is zero) so the field equation becomes:formula_4where "Rαγ" s the Ricci tensor, "gαγ" is the metric tensor, "R" the scalar curvature and κ is Einstein's constant we will calculate in the next section..
This equation can be written in another form, contracting indexes:formula_5Thus:formula_6where "T" is the scalar "Tαα" which we shall refer to as the Laue scalar.
Using this result we can write the field equation as: