1750
Steel magnets
John Michell, an English geologist, publishes A Treatise on Artificial Magnets, which describes how to make strong steel magnets and gives an account of his discovery of the inverse-square law for the attractive and repulsive forces of magnets.
1750
Aurora borealis
Perh Vilhelm Margentin writes a letter to the Swedish Academy of Sciences in which he comments on the effect of the aurora borealis on a magnetized needle.
1751
Franklin's electricity
Benjamin Franklin's letters to a colleague are published as Experiments and Observations on Electricity. The work includes Franklin’s views on positive and negative charges, the use of pointed conductors, improvements to the Leyden jar and a detailed plan for his famous kite experiment.1752
Kite experiment
The connection between lightning and electricity is proven when Benjamin Franklin’s plan to collect the charge from a storm cloud into a Leyden jar with a key attached to a kite is successfully completed.1759
Mathematical magnets
Franz Aepinus, a German natural philosopher, publishes his Tentamen Theoriae Electricitatis et Magnetismi (“An Attempt at a Theory of Electricity and Magnetism”), the first book to consider electricity and magnetism in terms of mathematics.
1762
Tongue tests
Johann Sulzer, a Swiss physicist living in Berlin, conceives and carries out an experiment that involves placing two dissimilar metals in his mouth so that they touch one another, producing a strange sensation in the tongue. This was essentially the first tongue test of a battery, and was repeated by many other scientists, including Alessandro Volta.1764
Electrophorus
Swedish physicist Johannes Wilcke invents a simple apparatus for producing substantial amounts of electric charge, which would later come to be known as the electrophorus.1767
Law of force
Joseph Priestley, an English pastor and science enthusiast, deduces that the law of force between electric charges must be the same as Newton’s inverse-square law for gravitational force. His History and Present State of Electricity is released, in which all data available in the field at the time is reviewed.
1768
Magnetic inclination
Johannes Wilcke compiles and publishes the first magnetic inclination chart that includes measurements from around the globe.
1769
Steam condensing engine
Scottish inventor James Watt contrives the steam condensing engine, a design he improves over the next two decades. The machine is used late in the following century for large-scale electricity generation.