This month we'll look at the BLOCK TYPE LRI, Fig. #1. The blocks have a hole which passes down through the insulator to accept the ground cable. In most cases this hole was round, but less often it was square.

Fig. #2 shows the block as mounted on a house. The block is held to the wall with a metal strap or bracket. This is shown around the center of the insulator. 

There is some variation in the shape of block LRIs. One style is shown in Fig. #3. Compare this with Fig. #1.

These are all glass blocks, as I'm not aware of any porcelain ones. There is one patent for blocks. This was a two-piece insulator (made to slip on at any point on the ground cable.) This was patented by C. H. LILLY of New York City on July 20, 1880. 

Right now I don't know of any blocks with embossing on them, but certainly they could exist.

I owe a special thanks to JOHN de SOUSA for information he supplied on block LRIs. 

Anyone with additional information, questions, or comments, please contact me at above address.