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Addressing the shortcomings of the Burr truss, namely its expense and specialized labor, Ithiel Town patented his lattice truss design in 1820. The lattice design fastened simple, diagonally set planks with treenails, or wooden pins, into crisscrossing truss system secured by top and bottom chords. Thus, Town's truss eliminated the need for large and expensive timbers, used in the Burr truss' series of arches, and streamlined the intricate, time-intensive labor of fastenig mortice-and-tenon joints into the simple slotting and wedging of treenails. Town's innovative truss design is visible today in two of Connecticut's three remaining covered bridges, Bull's Bridge in Kent and West Cornwall Bridge in Cornwall and Sharon.

What Is Libdex?
Libdex is a worldwide directory of library homepages, web-based OPACs,
Friends of the Library pages, and library e-commerce affiliate links.
The directory does not include links to terminal-based OPACs.

Until quite recently, I though that the first published HR diagram was constructed by Ejnar Hertzsprung for the stars of the Pleiades. Already in 1908, when Hertzsprung (then still an amateur astronomer with training in photochemistry) visited Karl Schwarzschild at Göttingen, he brought with him a working version with photographic magnitudes plotted against effective wavelengths. To determine the latter quantity, nowadays replaced by spectral type or color index, Hertzsprung attached a coarse diffraction grating before the objective so that an ordinary stellar image on the photographic plate was accompanied by a very short first-order spectrum on either side. The separation of the most intense parts of these spectra then directly translated into the effective wavelength of the star's light. However, this first Hertzsprung attempt to visualize the relation between luminosities and colors of stars suffered from a systematic error due to influence of the secondary spectrum of the objective. It was not until 1911, when the satisfactory version of the diagram was presented (Publ. Astrophys. Observ. Potsdam 22, 1, 1911) together with a color-magnitude diagram for another winter cluster, the Hyades.

Find out how electrocuting chickens (1775), getting laboratory assistants to put their hands in buckets of saline (1887), taking the ECG of a horse and following it to the slaughterhouse (1909), induction of indiscriminate angina attacks (1931), and hypothermic dogs (1953) have helped to improve our understanding of the ECG as a clinical tool. And why is the ECG labelled PQRST (1895)?

MedHist offers free access to a searchable catalogue of Internet sites and resources covering the history of medicine.

The Jane Goodall Institute advances the power of individuals to takeinformed and compassionate action to improve the environment for all living things. With Dr. Jane Goodall's words and example as guiding principles, the Institute inspires hope for a brighter future.

JARED DIAMOND is Professor of Geography at the University of California, Los Angeles. Until recently he was Professor of Physiology at the UCLA School of Medicine. He is the Pulitzer Prize-winning author of the widely acclaimed Guns, Germs, and Steel: the Fates of Human Societies, which also is the winner of Britain's 1998 Rhone-Poulenc Science Book Prize.

Fifty years ago, in 1947, it was common knowledge that there was a "Wall of Air" at the speed of sound. As an airplane neared this critical point, shock waves would buffet its wings and tail. The pilot would lose control, a condition then called "compressibility." Often, the airplane would shatter into pieces

Described as one of the 8 true geniuses, Von Kármán's inspiration for aeronautics came about during doctoral study at one of the world's foremost universities in the 1900s, Göttingen. After an all-night party in Paris, a friend suggested that, instead of going to sleep, they watch the French aviation pioneer Henri Farman fly his machine. Farman successfully completed a 2-kilometre (1.25-mile) course as Von Kármán embarked upon a long career in the aeronautical and astronautical sciences.

Agencies
Russian Space Agency
Home page for the Russian Space Agency (RKA) which was formed after the breakup of the former Soviet Union and the dissolution of the Soviet space program. The RKA uses the technology and launch sites that belonged to the former Soviet space program NASA mirror site
The Yuri Gagarin Cosmonauts Traing Center
Home page for the Yuri Gagarian Cosomonaut Training Centre at the Baikonur Cosmodrome. English and Russian versions.
Conquers of Space, a gallery of Soviet and Russian cosomonauts.
NASA Watch
Site often critical of NASA.
Animal Astronauts-Laika
Web page for Laika, the dog launched into orbit by the Soviet Union.