What is this?

1955 house in Garden Grove CA

I found this elec component in attic which looks like it has old fashioned tv tubes in it. There are also batteries in attic and little round plastic gizmos on family room ceiling beam.

Anybody know what it is?

Low voltage lighting control relays.

Heat activated fire alarm system?

Mike is all over the first photo. Most certainly low voltage control system with the exposed side the control side. The side internal to the wireway is the line side.

The second looks like you included to show the batteries you mentioned.

The third and fourth could possibly be an inline edison base fuseholder, but it is difficult to tell without seeing a side profile view.

The second pic looks like batteries used as backup power for a 12 volt DC solenoid shut-off valve for a propane system.

The last pics look like insulators for wire.

Last two pics are heat sensors, like the Klixon ones used in a coffee pot but wall mountable. Used for fire alarms.

Do you honestly believe this is a heat sensor?

I wonder where the fire alarm system is in this 1955 residential home.

I must say yes they are heat sensors. I just so the same system in a 1973 house in Central Florida above the air handler. After doing the research I found out that it was such. Pretty cool old system.