In one of the groups in VK I came across photographs of local reflow on brickwork:
Obvious melting on the brick, not a defect in bricks in the masonry. The place is located in India, Nalanda complex:
It looks like they tested the weapon.
This place is panoramic on a brick wall. In general, the Nalanda complex is an interesting place - some intricate structures or remnants of them:
Promotional video:
The place is included in the UNESCO list of cultural heritage. For anyone interested, the official story can be read on the Internet. I was interested in the place of reflow from the point of view of the melting point of materials.
The melting point of red brick is about 1200 g. And in the open air (on the wall) - the temperature should be even higher, because heat exchange (convection) appears. With what combustible substances could this have been done in the past? But let's not deviate in the direction of fantasies about ray weapons on an unknown principle and ancient blasters. Judging by the shapeless melted spot - the cause of a different nature.
There are examples of brick melting in the not so distant past:
Fort Zverev near Kronstadt. In one of the rooms something was burning and melted down the brick vaults.
Alexander's caponier of the Brest Fortress.
These are closed rooms and a high temperature could be created in them from fuel combustion. Gasoline burns at a temperature of 1300 gr. And the air draft of the catacombs created the effect of a horn (oxygen supply). But what about outdoor combustion?
Combustion temperature up to 1300 gr. has white phosphorus. But it doesn't stick to the walls. It's a powder. So he needed to be put into a state of napalm. Although napalm is made from gasoline and thickeners. There is even a high-temperature napalm, its combustion temperature reaches 1600 grams. (with the addition of magnesium and alkali metals). Could something similar be created in ancient times?
There are references in history about the "Greek fire". Officially, his recipe was lost in the 16th century. According to ancient scriptures, the Byzantines used it during sea battles:
Miniature from "Chronicle" of John Skilitsa.
An ancient handheld flamethrower (cheirosyphon) used in the siege of a fortress. Fragment of a miniature of the Poliorketika manuscript.
According to the descriptions, it looked like this:
Ancient analogue of flamethrowers. The following copies have survived:
Siphonophore or cheirosyphon for Greek fire.
Judging by the "mouth" of this weapon - it served for throwing fire, not cannonballs. It is possible that all supposedly ancient cannons are weapons for throwing Greek fire. Only after the invention of gunpowder did they switch to throwing nuclei.
According to modern assumptions, the "Greek fire" consisted of oil, saltpeter (as an inorganic oxidizer) and sulfur. In the descriptions, there is a mention that it could not be extinguished with water. And this is already an element of the modern supernapalm (with the addition of alkali metal alloys) and the supernapalm burns at a temperature of 1600 degrees, which is enough to melt bricks.
This is the version, the probable answer to this reflow on brick walls in India. Of course, we will not find mention of the use of Greek fire in India. But the very fact of reflow says that it was known there too.