How can 'reading' in 'carefully reading these papers' be a noun?

Question

Source: Rebecca Gowers. Plain Words (2014 ed). p. 222 Middle.

TROUBLE WITH VERBS

(1) ing endings
Words ending in ing are mostly verbal participles or gerunds, and, as we shall see, it is not always easy to say which is which. By way of introduction it will be enough to observe that when they are of the nature of participles they may be true verbs ('I was working') or adjectives ('a working agreement') or in rare cases prepositions ('concerning this question') or conjunctions ('supposing this happened'); if they are of the nature of gerunds they are always nouns ('I am pleased at his coming') — or rather a hybrid between a noun and a verb, for you may use the gerund with the construction either of a noun ('after the careful reading of these papers') or of a mixture between a verb and a noun ('after carefully reading these papers'). It is most confusing, but fortunately we are seldom called on to put a label on these words, and so I have preferred to give this section an indeterminate title.

'Carefully' is an adverb, and must qualify a verb. So how can the emboldened reading possibly be a noun, much less a mixture?

Answer 1

A gerund (-ing form of verb) can be used as a verb and a noun.

The reading - noun. Carefully reading - verb. This is why Gowers calls this use a "a mixture between a verb and a noun".

A gerund (/ˈdʒɛrənd, -ʌnd/ abbreviated ger) is a verb form that functions as a noun. Although similar to a verbal noun, the two are not identical, as a gerund retains properties of a verb, whereas a verbal noun does not; in English this is most evident in the fact that a gerund can be modified by an adverb and can take a direct object. The term "-ing form" is often used in English to refer to the gerund specifically.

Wikipedia (Gerund)

A gerund is a verb that also functions as a noun. For example, one can say one is engaged in the act of writing, but one can also say that what one is doing is a thing called writing.

Daily Writing Tips (Gerund)