MESSRS. EDITORS :In reading the discussion on hot air engines, published on page 310 of the present volume of the SCIENTIFIC AMERICAN, I noticed the question was asked, "Why its use was ...

The paint-stripping variety are pretty cheap, but not as cheap as [Porcas Pregos e Parafusos]’s home made hot air gun. This slightly hair-raising device is made from a variety of junk parts and ...

The attempt to substitute air for steam, as a motive power, is not so recent as is generally supposed, patents having been granted in this country as far back as 1824, for atmospheric engines.