Chicago and Northwestern line uses Brooks insulators

Brooks' Improved Paraffine Insulator.

GOOD insulation is the first and most essential requisite for satisfactory and efficient telegraphy. Without well insulated wires the best instruments and the most capable and experienced operators cannot make lines reliable or profitable. The improved Paraffine Insulator invented and manufactured by Mr. DAVID BROOKS, of Philadelphia, appears to be a nearly perfect insulator. Mr. BROOKS is daily in receipt of the most flattering testimonials in regard to the efficiency and reliability of his insulators. Among the latest is the following, which we publish by permission:

CHICAGO AND N. W. RAILWAY CO. TEL. DEP'T.

CHICAGO, June 14, 1869.

DAVID BROOKS, Esq., Philadelphia, Pa.

DEAR SIR. - It is a pleasure for me to add what little weight my testimony may have upon the merits of your insulators. We have one line between Chicago and Milwaukee (85 miles), insulated with the old style of three years standing, which has done us excellent service. We have one with the new between Chicago and Jamesville (91 miles), that has been up a year and a half, never failing us. It is immaterial whether the weather be rain or shine so far as its working is concerned. These are short circuits, and do not show the good qualities as strongly as longer lines, but they demonstrate the superiority of your insulator over the Wade or plain glass, there being wires of this description on the same poles with which frequent comparative tests have been made, greatly in your favor. The costs for repairs on these two lines have been very small, proving the economy of your insulator in actual outlay within a few years, if the quality of insulation was no consideration. I can heartily commend your insulators to the telegraph fraternity.

Yours truly,

GEO. H. BLISS.