The Beardslee magneto-electric telegraph instrument, developed in the 19th century, was an innovative method of communication but came with several technological limitations:

1. Power Source: The Beardslee telegraph utilized a magneto-electric generator which was hand-cranked. This manual operation made it less efficient and more labor-intensive than the later battery-powered systems.

2. Transmission Distance: The distance over which the Beardslee system could transmit signals was quite limited compared to other telegraphs that used more advanced electrical sources. This reduced its practicality for long-distance communication.

3. Signal Clarity: The signals sent via the Beardslee system could be less clear, especially over longer distances, due to the limitations of the mechanical and early electrical technology.

4. Speed: The reliance on manual cranking and less efficient signaling limited the speed at which messages could be sent compared to more advanced systems that used faster and more reliable electrical circuits.

5. Complexity and Training: Operating the Beardslee magneto-electric telegraph required a certain level of skill and training, which could be a barrier for widespread adoption.

These limitations reflect the early stage of telecommunication technology during the period the Beardslee telegraph was used. As technology evolved, these drawbacks were gradually addressed with the development of more advanced telegraph systems.