JF Ptak Science Books // Blog Bookstore

How Many Objects Can the Mind Embrace At One Time? (1871)

William Jevons.  "The Power of Numerical Discrimination", an article in Nature, 9 February 1871, occupying pp 281-283 (but a tightly-packed, tightly-printed 4,000 words) in the issue of pp 281-300.  Offered in the original weekly issue, removed from a larger bound vilume, but with the original front wrapper and 4-pp of ads.  Scarce in this format.  VG condition.  $250

• "IN an article with this title in a recent number of NATURE, Mr. W. S.
  Jevons offered the results of some ingenious experiments he had been
  making to determine how many objects the human mind could count by an
  instantaneous and apparently single act of attention. He comes to the
  conclusion that the power of his mind was limited to something less than
  five."--review in Nature 3, 367-367 (09 March 1871)

http://www.nature.com/nature/journal/v3/n71/abs/003367b0.html 

• "In a remarkable brief note in Nature, 1871, W. Stanley Jevons described the results of an experiment he had conducted on himself to determine the limits of the number of objects an observer could comprehend immediately without counting them.  This was an important philosophical question: How many objects can the mind embrace at once?"

"He carried out 1027 trials in which he tossed an "uncertain number" of
uniform black beans into a box and immediately attempted to estimate the number
"without the least hesitation".  His questions, procedure and analysis anticipated
by 75 years one of the most influential papers in modern cognitive psychology
by George Miller (1956), "The magical number 7 plus or minus 2: Some limits on
..."
For Jevons, the magical number was 4.5, representing an empirical law of
complete accuracy."-- By Vincent Arel-Bundock, http://vincentarelbundock.github.io/Rdatasets/doc/HistData/Jevons.html

Little Pieces and Superb Design: Rockets, Canons, and other Boom Boom

ITEMS:  two engravings from Heck' Iconographic Encyclopedia.  Each 11x8 inches, each printed in 1851.  Lovely condition.  $75/each.    Ref: JF Ptak Science Books  Post 1420

The Iconographic Encyclopedia of Johan Georg Heck (printed 1851)  turns out to be perhaps one of the best designed books of its type in the nineteenth century.  Seemingly no  matter how much diverse information is hosted per page, whether the items number in the dozens or over a hundred,  the artist managed to distribute them with such grace and apparent ease that it is an absolute pleasure to see it all arranged before you. 

Take for example the following two engravings of artillery fabrication of the early/mid 19th century.  There are 49 complex images on this first  piece of 11x8-inch paper (above), and yet there seems to be also a lot of white space.  It is a full but not crowded display of superb craftsmanship--it is also all very interesting. 

To start, the main figures at top-center shop the plan and elevation of a workshop for casting canons, and we can clearly see the main furnace ("A") for the big guns, surrounded by smaller auxiliary furnaces for smaller pieces.  Off to the side we see "K", which is the drawing room and also the place where the director of the plant would live. Underneath it all in section we see various pipes and drains used to take away water and ash.  The structure on the lower right is for forming the business end and the purpose of the canon or mortar--namely, the ammo, and in particular, the pattern mold of a 50-lb mortar.  The long vertical pole at left used to place he liquid metal under pressure in the hearth, the ball being at the very bottom center.

I've enlarged figures 4 and 5 to show the particulars of a canon (dry sand) mold, #4 being the exterior of the mold and #5 showing a cutaway so that one could see the six-ponder canon that was being formed inside.

There is just so much in this image that a more knowledgeable person could easily go on for pages describing each and every bit. 

The second image displays cartridges and (in general) fireworks--military pyrotechny.  What strikes me right away in this image are the five architecturals in the running vertically down the middle of the sheet.  They show what to do with gunpowder once it has been manufactured, which is an important consideration on handling and safety prior to it being used in battle--the first plan shows a field magazine, while the other four show the disposition of the construction of a permanent magazine, which show plenty of ventilation as well as massive walls which are in turn sunk into the earth and surrounded by ramparts.  It also seems that the roofing is huge, built no doubt to accommodate an earth filler.  Each of the barrels carried a hundred pounds of powder, so there was considerable interest not to allow the magazine to blow up, and if it did, to have the blast go mainly skyward. 

Some other items of interest in the second engraving include the incendiary devices (at bottom, #s 29+30),  signal rockets (#s 32,33,34,35), and the Congreve rocket, (#40 and #52,  which is much bigger and meant to be fired on the enemy, it being an incendiary); #53 is another Congreve, but this one scatters grenades as it is in flight. 

There's a lot that can be described here but it goes a little beyond what I wanted to do with this post--it is also a lot beyond what I know about the subject.

The Display of Information: How Many Planes does a Dreadnought Buy? (1911)

Item:  large (14x11) inch single page illustration fro The Illustrated London News for 1911.  SOLD   ref:  JF Ptak Science Books  Post 1408

There's nothing quite so satisfying as seeing a representation of quantitative data like this where the graphical displays are flying.  "One Dreadnought Buys 52 Dirigibles and 235 Aeroplanes" is a full-page diagram appearing in the 3 June 1911 , making a very strong point that in the new air-age 2 million pounds for one battleship buys a lot of aircraft.  Of course this is a British journal and the ship is flying an American flag--the image originally appeared in the Scientific American just a short while before this publication, and so it also enumerates American and international aircraft, making for a lovely representation of a broad range of airplanes filling up the same sky.