THERMO ELECTRIC PRODUCTS CO.
CD 1963046 E&MP 22.001
August 17, 1938
[sic] Inclosed please find a photograph of our new invention which represents a thermostat controlled hot water bottle heating unit, patented and registered under the name "TEPCO ELECTRIC HEATING UNIT".
This unit fits into the mouth of any standard hot water bag or bottle in place of the screw top. In the upper part of it, we have a thermostat made of Laminated steel with silver points, which controls the heat degree to which it is set. The unit is manufactured and housed in a heat and moisture resisting bakelite shell. It is accurate in holding the heat degree within two or three points. It forms NO gases, therefore is non-explosive. Water in the bottle makes the final electrical contact. There is no danger of any electrical shock as the unit carries a very low voltage. The electrical conductors on the inside of the unit are made of carbon, are non-corrosive and will give perfect service for many years.
The unit has been tested in several large laboratories in this country, with very satisfactory results as to accuracy in heat control and constant performance under the most severe conditions in water containing deposits of lime, heavy alkali, salt, potash and other minerals carried in water in different parts of the world. The unit can be set to any degree of heat required up to and including boiling point, without any danger to the conductors, or shock [sic] if electricity.
Please give us a write-up in your next issue of your magazine. We are sure your readers will welcome a news item of this kind. [sic] Inclosed please find a self addressed envelope for your favorable reply to our request.