Really nice view of a turn-of-the-century residential electric lighting distribution pole with a street series gooseneck streetlamp upon it. Note that the fixture-reflector part of the streetlight is attached to the end of its pipe-bracket via a metal clamp attached to a "mushroom" shaped insulator. CD 280 insulators were commonly used for this purpose as well as similarly designed porcelain ones. This method of attachment/fixture design was popular through around 1910, electrically insulating the lamp fixture from hazardous high voltages sometimes inherent with series lighting circuits (also note the break-arm on the middle crossarm separating the two wires leading down to the fixture...)