Where is the seventh gym on Pokemon FireRed?

The 7th Gym Leader is Blaine in Cinnabar Island. He uses nothing but Fire Pokèmon. I used a lvl 32 Seel and beat the first Pokèmon(Growlithe) with "Surf"(always use a good move twice in a row if you don't take him out in one shot because he'll use Hyper Potion.) I also used a lvl 29 Seadra with "Surf" to beat second Pokèmon(Ponyta.)And I used a lvl 31 Snorlax using "Surf" to beat the third Pokèmon(Rapidash.) And a lvl 36 Snorlax using "Body Slam"(move) and "Rest"(move) to beat the last Pokèmon(Arcanine.)

His Pokèmon are Growlithe(LVL 42), Ponyta(LVL 40), Rapidash(LVL 42), and Arcanine(LVL 47)
The 7th gym is on Cinnabar island. The gym leader is Blaine and he uses fire types. Find the key to his gym in Pokemon mansion.