Where to find Alethiometer symbols
I haven't found all the symbols, but I know where to find a lot of them and this is where to find them:
Jordan College:
I found two symbols at Jordan College. They are located here:
After escaping from Mrs Lonsdale onto the roof and got past the windows without the adults seeing you, you will see Roger. Go and talk to him. You will have the opportunity to spit Plum Pits onto the scholars below. Hit three Scholars then before you go to to play Cat and Hare with The Tanners a Compass meaning will appear. It is this meaning : Candle-Learning.
After you beat the Tanners at Cat and Hare, Roger will suggest you going to the Retiring Room. Lyra will agree and jump down from the rooftops. Pan must use his Sloth form to get to the door by swinging across the poles to the courtyard. When you get to the door, don't go through it yet. Swing on the pole that you just swung on and let go. You will land on a small
platform. Swing on the next pole and you'll come to another. Jump back onto the rooftops and you will see another Sloth pole. Swing across this and you will get the Compass meaning : Alpha and Omega - Process. Make your own way back to where you began to swing across Sloth poles and then you can go through to Courtyard door.
London:
In Mrs Coulters flat, there are lots of Compass meanings. Begin in Lyra's room. Jump on the bed. Keep jumping until a Compass meaning comes up. I can't exactly remember what it is though. Then on Lyra's make up table below the map, press interact on the triangle button. When Pan and Lyra finish speaking, use Ermine Insight to find the apple. An exclamation mark should appear when Pan finds it. Then you will learn : Apple-Vanity. Then go through the open door at the back of the room. You will come across a bathroom. Click the triangle button next to the bath when it appears on the screen. Lyra will say that there is no Stopper. you will find it later on in the level. Then go out of the bathroom and through the bedroom and open the doorway out. Pan will say you can't get in Coulter's office through the door opposite the bedroom and they should find another way. Then look out the window next to the office door. Use Ermine Insight. you will have learned: Tree - Firmness. Then go through the next door into a room with Mrs Coulter's servants. Hide behind the wardrobe (Your not timed). Pan will have to fight the monkey. Lyra will throw vases at it now and then. If you never miss when throwing the vases, another compass meaning will appear. Go out the room after you defeat the monkey and down the stairs. Don't go into into the room downstairs or the servant will catch you. On the unit next to the room, there is a Tub Stopper. Pick it up and take it to the bathroom in your room. Put it in the bath. The bath will fill up. Use Ermine Insight and move the cursor over the dolphin. You will have learned: Dolphin - Water. Then go out the bathroom, through the bedroom, through the room where the servants WHERE, and into the room at the top of the stairs. Hide in the fireplace. DO NOT EXIT. When the maid has gone, somewhere in the room there is a marionette. Use Ermine Insight to look for it. You will then have learned: Marionette - Grace.
I'm not really any further on the game. Good Luck!