Page:Popular Science Monthly Volume 90.djvu/194

 Bottles, Bottles Everywhere, But Not A

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��The basis of bottle glass is a siliceous sand, limestone and either sulphate or carbonate of soda. The photograph above shows the new mixture together with broken bottles being thrown into the furnace. Here it melts and forms a thick syrupy liquid which is later molded into the form of bottles

��The photograph below shows another kind of raw material used for bottle-making — "cullet." It is a by-product of the glass furnaces and it is melted with the other raw materials. A combination of "cullet," sand, soda ash and lime gives a white glass with a very slight greenish tone

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���At left: Placing the bottles in an oven for gradual cooling. After they have been formed in the mold the bottles cool quickly on the outside while they remain at a high temperature within. To produce a clear, strong bottle a twelve-hour cooling is necessary

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