Original 1921 electrical trade vintage magazine ad for the JEFFERY-DEWITT INSULATOR COMPANY. Main office and plant were located in Huntington, WV.

Manufacturers of J-D Insulators. 

The Quality of Raw Materials in J-D Insulators is Uniformly Good.

One of the first difficulties encountered by the insulator manufacturer is that securing raw materials which is uniform in quality year in and year out. Where price fluctuations and transportation difficulties make it impossible to secure continuous supply of feldspar rock from the same mine the quality of the finished insulator is sure to vary because the characteristics of the feldspar rock from each mine are different.

In the manufacture of JD insulators the raw material problem has been solved by the purchase of our own source of supply, a mine containing an enormous deposit of first quality feldspar.

This rock comes to our plant in the form as shown in the photograph. It is then carefully sorted by hand and ground in what we think is the most up to date grinding equipment in the country.

Has product image, description and application provide product details.

Unbound from a rare 1921 Electrical World magazine, this unique old one-page technical magazine advertisement would display beautifully matted and framed. Nice graphics. A fabulous addition to your retro electrical insulator library.