But, more impressive even than this, are his observations about the aortic valve which he made while experimenting with an ox’s heart.
He was interested in the way the aortic valve opens and closes to ensure that blood flows in one direction.
So, he constructed a model by filling a bovine heart with wax. Once the wax hardened, he recreated the structure in glass and them pumped water mixed with grass seeds through it.
This allowed him to observe tiny vortices as the seeds swirled around in the widened root of the aorta. This allowed him to correctly posit that these vortices helped to close the aortic valve.
Since he never published his journals, this was not understood until the 20th century. In 1968, two engineers in Oxford demonstrated it. The only reference in the paper was to Leonardo.
His studies of anatomy may have proved useful in helping him develop some of his inventions.
For instance, by studying how muscles worked, he may have gained insight into how to approximate human motion using mechanical means.
This is often referred to as a machine gun, however, it is not the same kind of “machine gun” we know today. It was composed of 33 small-caliber guns, likely hand muskets.
These 33 guns were divided into three rows of 11 guns each. They were connected to a revolving platform and attached to this platform were large wheels.
All 33 guns would be loaded and then all 11 guns from the first row would be fired. The platform was then rotated so that the next row of guns could be aimed. The first row of guns could then cool down and the third row could be loaded and ready to fire.
But why is it referred to as an organ? It is because the rows of guns resemble the pipes of an organ.
As far as we know, one of these has not been built in modern times, unlike some of his other inventions. However, we can imagine it would have made an effective and deadly weapon of war.
This huge bronze horse was commissioned in 1482 by the Duke of Milan and was to be 24-feet tall.
The construction of this mammoth horse required making it out of a solid piece of bronze coming in at 80 tons.
Leonardo used his experience of building bronze cannons to help plan how to build the bronze horse. It required him to invent new mold-making techniques and an innovative oven to reach the high temperatures required to melt so much bronze.
Leonardo had finally solved all the problems required to create the huge horse when tragedy struck. In 1494, King Charles invaded France. In order to delay King Charles, the Duke offered King Charles a bribe of the bronze set aside for the creation of the horse.
Which was less than helpful, as the French simply used the bronze to make cannons.
In 1977, a retired airline pilot and artist, one Charles Dent decided to create the horse. He spent 17 years working on it before he died in 1994.
However, in 1999, the horse was completed and gifted to the people of Milan in Italy.