Alomancy also called Adromancy, ydromancie, idromancie, and halomancy, is an ancient form of divination

Divination

Divination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...

. Similar to many other forms of divination, the diviner casts salt

Salt

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 crystals into the air and interprets the patterns as it falls to the ground or travels through the air. The diviner can also interpret patterns formed from the residue of a salt solution

Solution

In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

 as it evaporates in the bowl. The exact interpretations are unknown, but it probably follows a similar method to aleuromancy.

Salt itself is often intertwined with luck

Luck

Luck or fortuity is good fortune which occurs beyond one's control, without regard to one's will, intention, or desired result. There are at least two senses people usually mean when they use the term, the prescriptive sense and the descriptive sense...

 and some of this ancient tradition can be seen in the superstition

Superstition

Superstition is a belief in supernatural causality: that one event leads to the cause of another without any process in the physical world linking the two events....

s, such as perceived misfortune when the salt cellar is overturned and the custom of throwing salt over the left shoulder for good luck.
One form of Alomancy consists of the casting of salt into a fire, which is considered a type of Pyromancy

Pyromancy

Pyromancy is the art of divination by means of fire.-History of pyromancy:Due to the importance of fire in society from the earliest of times, it is quite likely that pyromancy was one of the earlier forms of divination...

.