He served in the military engineering corps under King Charles XII during the siege of Fredrikshald (now Halden, Norway). He assists in the transportation of ships over land, showcasing his engineering skills and innovative thinking.

As Assessor Extraordinary to the Board of Mines, Swedenborg works on improving mining techniques, developing new methods for smelting copper and iron, and writing extensively on metallurgy and mineralogy. He demonstrates a keen understanding of practical engineering and scientific principles.

Swedenborg publishes 'Miscellanea Observata circa Res Naturales' (Miscellaneous Observations Connected to Physical Matters), a multi-volume work containing articles on various scientific and philosophical subjects, including astronomy, mathematics, and physics. It showcases his wide-ranging intellectual interests.

Swedenborg founds the 'Daedalus Hyperboreus,' Sweden's first scientific journal. He publishes articles on various topics, including his own inventions and scientific observations, aiming to promote scientific knowledge and technological innovation in Sweden.

Swedenborg publishes 'Opera Philosophica et Mineralia' (Philosophical and Mineralogical Works), a three-volume work that includes his theory on the origin of the universe (Principia rerum naturalium, sive novorum tentaminum phaenomena mundi explicandi), a treatise on iron, and a treatise on copper. This work showcases his ambition to develop a comprehensive philosophical and scientific system. It includes his nebular hypothesis, predating similar theories later proposed by Kant and Laplace.

Swedenborg embarks on an intensive study of human anatomy and physiology, seeking to understand the connection between the soul and the body. He dissects cadavers, reads extensively, and develops his own theories about the structure and function of the human body. This research lays the groundwork for his later spiritual and philosophical inquiries.

Swedenborg publishes 'Oeconomia Regni Animalis' (The Economy of the Animal Kingdom), a two-volume work exploring the circulation of the blood, the anatomy of the brain, and the general physiology of the human body. He anticipates some modern neurological concepts.

Swedenborg’s scientific investigations increasingly focus on understanding the relationship between the physical and spiritual realms. He intensely searches for the 'seat of the soul' within the human body. This quest marks a transition from purely scientific pursuits to philosophical and ultimately theological inquiries.