"It is a mistake to sprinkle salt into the air" is an inverted sentence. Belongs to prepositional object structure. The normal modern word order should be: it can almost be compared to sprinkling salt in the air. In the poem, the verb-object phrase "sprinkling salt in the air" comes first.
Modern Chinese:
The common inversion sentences in modern Chinese are: verb inversion, attribute, adverbial and head inversion. Inverted sentences are mainly used to emphasize something.
Subject-predicate structure
Subject comes first and predicate comes last, which is a normal and universal word order. Sometimes, conversely, the predicate comes first, which is the most common variant sentence. This phenomenon is common in interrogative sentences, imperative sentences and exclamatory sentences. There is usually a pause between the predicate and the subject, which is separated by commas when writing. Composition: "predicate" case. For example:
Where are you going to find it?
Don't worry, mom and dad! (imperative sentence).
Finally passed, the rule of the last dynasty in China! (exclamatory sentence).
This is often to emphasize the predicate, or to say the main point before adding the subject. Subjects usually read softly.