Twine phones
The string telephones which for several years have been flooding the boulevards and the streets of the different cities of Europe, and whose invention dates back, as we have seen, to the year 1667, are very interesting apparatuses by them themselves, and we are astonished that they did not appear rather in the physics cabinets. They consist of cylindrical-conical tubes of metal or cardboard, one end of which is closed by a stretched membrane of parchment, in the center of which is fixed by a knot the string or cord intended to bring them together. When two tubes of this kind are thus joined together and that the wire is tight, as shown, it suffices for a person to apply one of these tubes against the ear and for another person to speak very close to the opening of the other tube, so that all the words spoken by the latter are immediately transmitted to the other, and one can even converse in this manner in an almost low voice.
breechloader
Under the Swedish warrior Gustavus Adolphus, artillery began to take its true position on the field of battle. Gustavus saw the need for mobility, so he divorced anything heavier than a 12-pounder from his field artillery. His famous "leatheren" gun was so light that it could be drawn and served by two men. This gun was a wrought-copper tube screwed into a chambered brass breech, bound with four iron hoops. The copper tube was covered with layers of mastic, wrapped firmly with cords, then coated with an equalizing layer of plaster. A cover of leather, boiled and varnished, completed the gun. Naturally, the piece could withstand only a small charge, but it was highly mobile.
Brick House at Jamestown
Brick House at Jamestown, about 1640. (Conjectural sketch by Sidney E. King.)
French Garrison Gun
French Garrison Gun (1650-1700). The gun is on a sloping wooden platform at the embrasure. Note the heavy bed on which the cheeks of the carriage rest and the built-in skid under the center of the rear axletree.
Light Artillery of Gustavus Adolphus
Gustavus abandoned the leather gun, however, in favor of a cast-iron 4-pounder and a 9-pounder demiculverin produced by his bright young artillery chief, Lennart Torstensson. The demiculverin was classed as the "feildpeece" par excellence, while the 4-pounder was so light (about 500 pounds) that two horses could pull it in the field.