"The air pump is an engine by which the air can be pumped out of a vessel, or withdrawn from it. The vessel so exhausted, is called a receive, and the space thus left in the vessel, after withdrawing the air, is called a vacuum. The principles on which the air pump is constructed are readily understood, and are the same in all instruments of this kind, though the form of the instrument itself is often considerably modified. Let R be a glass vessel, or receiver, closed at the top, and open at the bottom, standing on a perfectly smooth surface, which is called the plate of the air pump. Through thie plate is an aperture, which communicates with the inside of the receiver, and the barrel of the pump. The piston rod works air tight through the barrel. At the extremity of the barrel, there is a valve which opens upwards, and is closed as the piston rises." —Comstock, 1850

Air Pump

"The air pump is an engine by which the air can be pumped out of a vessel, or withdrawn from it. The…

"The piston rods are furnished with racks, or teeth, and are worked by the toothed wheel a, which is turned backwards and forwards, by the lever and handle b. The exhaustion pipe c, leads to the plate on which the receiver stants. The valves v, n, u, and m, all open upwards." —Comstock, 1850

Air Pump

"The piston rods are furnished with racks, or teeth, and are worked by the toothed wheel a, which is…

"The drum armature differs from the shuttle armature chiefly in that it employs many coils instead of one. The cylindrical iron core is made of thin disks of soft iron in insulated from each other, thus minimizing the 'local currents' and the heating effects thereof." — Avery, 1895

Drum armature

"The drum armature differs from the shuttle armature chiefly in that it employs many coils instead of…

"Section of Bamboo, showing an angular network of cells, and the round apertures of pitted vessels." — Encyclopedia Britanica, 1893

Bamboo

"Section of Bamboo, showing an angular network of cells, and the round apertures of pitted vessels."…

"Camera obscura strictly signifies a darkened chamber, because the room must be darkened, in order to observe its effects. To witness the phenomena of this instrument, let a room be closed in every direction, so as to exclude the light. Then from an aperture, say of an inch in diameter, admit a single beam of light, and the images of external things, such as trees and houses, and persons walking the streets, will be seen inverted on the wall opposite to where the light is admitted, or on a screen of white paper, placed before the aperture. The reason why the image is inverted will be obvious, when it is remembered that the rays proceeding from the extremities of the object must converge in order to pass through the small aperture; and as the rays of light always proceed in straight lines, they must cross each other at the point of admission. Thus the pencil a, coming from the upperpart of the tower, and proceeding straight, will represent the image of the part at b, while the lower part c, for the same reason, will be represented at d." —Comstock, 1850

Camera Obscura

"Camera obscura strictly signifies a darkened chamber, because the room must be darkened, in order to…

"Camera obscura strictly signifies a darkened chamber, because the room must be darkened, in order to observe its effects. To witness the phenomena of this instrument, let a room be closed in every direction, so as to exclude the light. Then from an aperture, say of an inch in diameter, admit a single beam of light, and the images of external things, such as trees and houses, and persons walking the streets, will be seen inverted on the wall opposite to where the light is admitted, or on a screen of white paper, placed before the aperture. The reason why the image is inverted will be obvious, when it is remembered that the rays proceeding from the extremities of the object must converge in order to pass through the small aperture; and as the rays of light always proceed in straight lines, they must cross each other at the point of admission. Thus the pencil a, coming from the upperpart of the tower, and proceeding straight, will represent the image of the part at b, while the lower part c, for the same reason, will be represented at d." —Comstock, 1850

Camera Obscura

"Camera obscura strictly signifies a darkened chamber, because the room must be darkened, in order to…

"The photographer's camera corresponds to the camera-obscura. A darkened box, adjustable in length, takes the place of the darkened room, and an achromatic convex lens is substituted for the aperture in the shutter." — Avery, 1895

Bellows camera

"The photographer's camera corresponds to the camera-obscura. A darkened box, adjustable in length,…

"Longitudinal and Vertical section of the skull of a dog, with mandible and hyoid arch. an, anterior narial aperture; MT, maxillo-turbinal bone; ET, the ethmo-turbinal; Fr, frontal; Pa, pariental; IP, interparietal; SO, supra-occipital; ExO, sphenoid; OS, orbito-sphenoid; PS, presphenoid; Pl, palatine; Vo, vomer; Mx, maxilla; PMx, premaxilla; sh, stylo-hyal; eh, epi-hyal; ch, cerato-hyal; bh, basihyal; th, thyro-hyal; s, symphysis of mandible; cp, coronoid process; cd, condyle; a, angle; id, inferior dental canal. The mandible is displaced downwards, to show its entire form; the * indicated the part of the cranium to which the condyle is articulated." —The Encyclopedia Britannica, 1903

Dog Skull

"Longitudinal and Vertical section of the skull of a dog, with mandible and hyoid arch. an, anterior…

"Liphistius desultor. Under side of the uplifted genital or first opisthosomatic somite of the female; g, genital aperture; p, pitted plate, probably a gland for the secretion of adhesive material for the eggs; l, the edges of the lamellae of the lung-books of the first pair." — The Encyclopedia Britannica, 1910

Liphistius Desultor

"Liphistius desultor. Under side of the uplifted genital or first opisthosomatic somite of the female;…

"A compound foraminiferan, Nodosaria. a, aperture of shell; f, food particles captured by the strands of protoplasm outside the shell; n, nucleus; sh, shell, 1-4, the successive chambers of the shell; 1, being the oldest." — Galloway

Nodosaria

"A compound foraminiferan, Nodosaria. a, aperture of shell; f, food particles captured by the strands…

"Solar Spectrum.—If a ray, proceeding from the sun, be admitted into a darkened chamber, through an aperture in the window shutter, and allowed to pass through a triangular shaped piece of glass, called a prism, the light will be decomposed, and instead of a spot of white, there will be seen, on the opposite wall, a most brilliant display of colors, including all those seen in the rainbow." —Comstock, 1850

Solar Spectrum

"Solar Spectrum.—If a ray, proceeding from the sun, be admitted into a darkened chamber, through…

"Thelyphonus assamensis, Ventral surface of the anterior region of the opisthosoma, the first somite being pushed upwards and forwards so as to expose the subjacent structures. opistho 1, First somite of the opisthosoma; opistho 2, second do.; g, genital aperture; l, edges of the lamellae of the lung-books; m, stigmata of tergo-sternal muscles." — The Encyclopedia Britannica, 1910

Thelyphonus assamensis

"Thelyphonus assamensis, Ventral surface of the anterior region of the opisthosoma, the first somite…

A sash window is made of one or more movable panels or sashes that form a frame to hold panes of glass which are often separated from other panes by narrow muntin bars

Interchangeable Window Sash and Screen

A sash window is made of one or more movable panels or sashes that form a frame to hold panes of glass…

A window with a hinged sash that swings in or out like a door comprising either a side-hung, top-hung, or occasionally bottom-hung sash or a combination of these types, sometimes with fixed panels on one or more sides of the sash.

Casement Window

A window with a hinged sash that swings in or out like a door comprising either a side-hung, top-hung,…