Pronunciation of 'gyroscope' in the late 19C

Reading a question relating to portmanteau words has prompted me to ask this question. The reason is that Charles Dodgson writing as Lewis Carroll included the line

Did gyre and gimble in the wabe

in the nonsense poem Jabberwocky as part of Through the Looking Glass and What Alice Found There.

There are many strange invented words in the poem but some of them are explained later in a conversation between Alice and Humpty Dumpty including ‘gyre’, ‘gimble’ and Dodgson’s new invention ‘portmateau words’ such as ‘slithy’ and ‘mimsy’. ‘Gyre’ is defined as "to go round and round like a gyroscope" and ‘gimble’ as "to bore holes like a gimlet"

I’ve known and enjoyed the poem for years and, because "gyre" is said by Humpty Dumpty to be derived from "gyroscope", I’ve always pronounced it with a ‘soft’ g or [ʒ].

However I have heard several other people, including respected actors on commercial records, pronounce it with a ‘hard’ g or [g] thus producing alliteration between ‘gyre’ and ‘gimble’ which the soft g does not.

On looking up the etymology of ‘gyroscope’ I find that it is of French origin and that the French pronounce it with an even softer g than English speakers do. I also find that its origin is the Greek word γύρος (gyros, ‘circle’ or ‘turn’). This starts with a gamma which the Greeks do not pronounce at all like a g in either French or English and certainly not like an English [g].

My question, finally, is this:

Was the word ‘gyroscope’ pronounced with a hard g [g] in Dodgson’s time (second half of the 19th century), even if only at Oxford University, or am I correct in my pronunciation of ‘gyre’ producing only a very slight alliterative effect with ‘gimble’?