The precautions needed while reading a laboratory thermometer are:
1- It should be kept upright not tilted.
2- Bulb should be surrounded from all sides by the substance of which the temperature is to be measured.
3- The bulb should not touch the surface of the container.

Precautions while using a laboratory thermometer:

1. Handling with care:
- Always handle the laboratory thermometer with care to prevent any damage or breakage.
- Hold it from the top end or use a holder designed for thermometers to avoid accidents.

2. Avoid direct contact with hot surfaces:
- Do not touch the thermometer directly to any hot surface as it can lead to inaccurate readings and may cause burns.
- Use tongs or a suitable holder to measure the temperature of hot objects.

3. Clean the thermometer before and after use:
- Ensure that the thermometer is clean before using it to avoid any contamination that could affect the accuracy of the readings.
- After use, clean the thermometer with a suitable cleaning agent and rinse it thoroughly.

4. Avoid extreme temperature changes:
- Avoid exposing the thermometer to extreme temperature changes as it can cause damage to the instrument.
- Gradually acclimate the thermometer to the temperature of the environment before taking measurements.

5. Use appropriate measuring range:
- Use a thermometer with an appropriate measuring range for the intended application.
- Using a thermometer with a lower or higher range can result in inaccurate readings and potential damage.

6. Read the thermometer at eye level:
- Read the thermometer at eye level to minimize parallax error, which occurs when the reading is affected by the angle from which it is viewed.
- Position yourself in front of the thermometer to ensure accurate readings.

7. Do not immerse the entire thermometer:
- Avoid immersing the entire thermometer in liquids, especially if it is not designed for such use.
- Follow the manufacturer's instructions regarding the appropriate immersion depth for liquid measurements.

8. Check for zero error:
- Before use, check if there is any zero error present in the thermometer.
- If there is a zero error, take note of it and adjust the readings accordingly.

9. Keep away from children:
- Store the laboratory thermometer in a safe place, out of reach of children to prevent accidents or misuse.

10. Report any damage or malfunction:
- If you notice any damage or malfunction in the laboratory thermometer, report it immediately to the concerned authority.
- Avoid using a damaged thermometer as it can lead to inaccurate readings and potential hazards.

Following these precautions will help ensure accurate measurements, maintain the lifespan of the laboratory thermometer, and ensure the safety of the user and the surrounding environment.