Bacon is not a (naive) empiricist. His works are full of criticisms of „blind experience” and biased experiments. His new experimentalism is based on two things: 1) new kinds of experiments („subtle enough”) and 2.) a new art of experimentation which can function as a guide into the „woods of experience”.
A new class of experiments
[…] we are surely looking for a class of experiments much more subtle and simple than those which we just bump into. For I am unearthing and adumbrating many things which no one who was not pressing forward on a certain and direct road to the discovery of causes would have thought to investigate; for in themselves these things have no great use, and are quite obviously not sought out for their own sake but stand in the same relation to things and works as the letters of the alphabet do to speech and words which, though useless in themselves, are still the fundamental elements of all discourse. (OFB XI 40-1).
In the end, Bacon proposed not one, but two classes of experiments (both, presumably, fulfilling the requirements formulated above). They are the „experiments of light” (experimenta lucifera) and the „experiments of fruit” (experimenta fructifera).
Experiments of light
Experiments of light are directed towards understanding and discovery. Bacon notoriously (and somewhat confusedly) claims that „they have no use in themselves”; they are tools contributing to the discovery of causes. These experiments have two interesting features. First, they have a curious instrumental character. They function as a torch: they illuminate some of the dark corners of nature. More precisely, Bacon claims that experiments of light are throwing light on the basic constituents of the universe, i.e., the simple natures. Second, experiments of light „never fail”: since they are not designed to test but to inquire, they always give insightful answers to our genuine questions addressed to nature.
[…] experiments of no use in themselves, but which only contribute to the discovery of causes, which experiments I have grown used to calling Light-bearing (lucifera) as against Fruit-bearing ones. Now these former have a marvelous virtue and quality to them, namely that they never fail or let you down. For since we bring them in not to accomplish any work but to show the natural cause in something, they suit their purpose whichever way they turn out because they settle the question.(OFB XI 157-9 )