Current mood:	sleepy
Entry tags:	flight, foody, science

Your trivia for the day

• Oct. 3, 2008 | There you are, belted in for landing, at a window seat in Row 36. The approach is smooth, the weather clear, the landing gear drops into place. Down, down, down you come. At 500 feet or so, you can make out the writing on billboards; touchdown is only seconds away.

  Then, without warning, the engines roar and the aircraft pitches up sharply. For a second or two the plane seems to wallow, uncertain which direction it wants to take, momentum pushing downward against the sudden burst of power and raising of the nose. Hydraulic pumps whine, gear doors clunk open, turbines scream. The plane begins to climb, groaning and shuddering as the landing gear retracts and the flaps are reset. The ground falls away; the plane banks sharply. You grip the armrest. What the heck is happening?

  ...

  The maneuver is called a "go-around," and it is known to scare the daylights out of passengers. Go-arounds have a special place in the pantheon of anxious flier concerns, up there with the likes of turbulence and wind shear. I read about them all the time, luridly described in letters from fliers, novices and seasoned travelers alike, anxious to know what might have gone wrong, wondering if they narrowly escaped a collision.

  In fact, go-arounds are fairly common and seldom the result of anything dangerous. In most cases it's a minor spacing issue: Two arriving planes are no longer able to maintain the required separation parameters, and/or the aircraft ahead has not yet vacated the runway. Not an ideal situation, but let's be clear: This is not the same thing as a proverbial near miss. In all likelihood, the reason your plane is going around is to prevent a near miss. Actual instances where a collision is narrowly averted do occur, but they are extremely rare.

  Other times, traffic has nothing to do with it. A variant of the go-around, spoken of somewhat interchangeably, is the "missed approach," when a plane pulls off the same basic maneuver for weather-related reasons. If, in the course of an instrument approach, visibility drops below a prescribed value, or the plane has not made visual contact with the runway upon reaching the minimum allowable altitude, the crew must climb away (often followed by a diversion to an alternative airport). A go-around will also be initiated any time an approach becomes unstable. Glide-path deviations, a too-high rate of descent, severe crosswinds, a wind-shear alarm -- any of these can trigger one.

  ...

  From a pilot's perspective, these maneuvers are not terribly difficult, but the workload is very high. (Either pilot -- captain or first officer -- can be at the controls, but generally it is the captain who makes the "go-around" or "missed-approach" call.) The first step is advancing the power to go-around thrust, retracting flaps and slats to an intermediate position, and rotating to a target pitch -- somewhere around 15 degrees nose up, depending on the aircraft. Once a climb is safely established, the landing gear is raised. Next, flaps and slats are retracted, followed by additional power and pitch adjustments. Some of this happens automatically, the rest is accomplished by hand. The steps are not random or subjective; they are performed at specific speeds and altitudes. Once at level-off, the flight management system may need to be reprogrammed -- the autoflight components appropriately reset, checklists run, the weather double-checked and so on. All of this while taking instructions (turns, climbs, etc.) from air traffic control. There's lots of talking and a rapid succession of tasks.

  All in all, there are few busier times in a cockpit. This is one of the reasons you often don't hear from the pilots for several minutes.

  (From Ask the pilot, Salon)



• Sugar of Lead
  Isn't that an interesting name? It used to be a common sweetener until people caught on to the poisonous aspect.

  Lead(II) acetate is a chemical compound, a white crystalline substance with a sweetish taste. It is made by treating litharge (lead(II) oxide, PbO) with acetic acid. Like other lead compounds, it is very toxic. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate, Pb(CH₃COO)₂·3H₂O, a colorless or white efflorescent monoclinic crystalline substance. Lead(II) acetate is also known as lead acetate, lead diacetate, plumbous acetate, sugar of lead, lead sugar, salt of Saturn, and Goulard's powder (after Thomas Goulard).

  The substance is used as a reagent to make other lead compounds and as a fixative for some dyes. In low concentrations, it is the principal active ingredient in progressive types of hair coloring dyes. Lead(II) acetate is also used as a mordant in textile printing and dyeing, as a drier in paints and varnishes, and in preparing other lead compounds.

  Lead acetate has a sweet taste, which has led to its use as a sugar substitute throughout history. The ancient Romans, who had few sweeteners besides honey, would boil must (grape juice) in lead pots to produce a reduced sugar syrup called defrutum, concentrated again into sapa. This syrup was used to sweeten wine, and to sweeten and preserve fruit. It is possible that lead acetate or other lead compounds leaching into the syrup might have caused lead poisoning in anyone consuming it.^[1]

  
  It also used to be a medicine.

  Dose. 1/2 gr. to 3 gr., or more; of Pilula Plumbi cum Opio, 4 gr. to 8 gr.

  Liquor Plumbi Subacetatis. Solution of Subacetate of Lead. Prep. (Acetate of lead, five ounces; litharge, in powder, three ounces and a half; distilled water, twenty fluid ounces, or a sufficiency. Boil them together for half an hour, frequently stirring, 9 then filter; and when the liquor is cold, add of distilled water as much as may be necessary, that it may accurately measure twenty fluid ounces. Let it be kept in well-closed vessels.) By the action of the litharge on acetate of lead, a sub-salt is formed, an additional amount of the oxide of lead entering into the composition of the salt.

  Therapeutics. Acetate of lead in small doses acts as a sedative and astringent, lessening morbid mucous discharges and haemorrhages, and even diminishing the natural secretions; hence producing constipation, thirst, and a species of colic named Painters' or lead colic, accompanied by a peculiar blue line on the gums (a valuable diagnostic sign): when continued for some time, it renders the pulse smaller, and induces wasting of the body; it also produces an influence on the nervous system, shown by loss of power of the extensors of the hand', sometimes complete paralysis and apoplexy. The serious symptoms above described are, for the most part, brought on by contact with lead in various occupations, and not often by its employment as a medicine. Acetate of lead is much used in haemorrhages from various organs, also in chronic diarrhoea and dysentery; in phthisis to check expectoration and excessive sweating. Externally it is sedative and astringent, and is sometimes used in skin affections and over inflamed parts.

  
  It can even be used for laundering, to help preserve the colour of older dyes.

  Have you noticed some lipsticks taste sweet on your lips even though, when you read the ingredient list, they contain no sugar or other sweeteners... well... except the lead acetate. Lead acetate is found in red lipsticks more than other colors. The chemical helps with colorfastness, which is why it's also using in dyeing, including progressive hair color, like Grecian Formula™ for men. You can have a head of youthfully dark hair, all the better to attract that lovely lady with the ruby red lips and the sweet, sweet kiss.

  
  And apparently it's also a band, but what isn't nowadays?



• Four Thieves Vinegar
  The stories are told very similarly - during the Plague (the Black Death in Europe), four thieves did quite well for themselves robbing the houses of the infected, but never sickening themselves (not even morally, it seems). They made a deal to escape being hung — they would give up the secret herbal recipe given them as a protectant.
  
  Unprovable, but the recipe itself is interesting for the value of the herbs used in combination with the vinegar, and it does indeed have beneficial properties both internally and externally — although stress-testing it is not recommended. It also makes an excellent salad dressing. The ingredients most of the recipes have in common is unpasteurised apple vinegar (at wholefoods stores and such) — sometimes some variety of wine vinegar — and garlic. The other herbs, added and cold-steeped for a fortnight before adding the garlic, are:
  
  
  • Angelica *
  • Black Pepper (oil) *
  • Calamus *
  • Capiscum (oil) *
  • Cinnamon * ~
  • Cloves ***~
  • Echinacea (tincture) *
  • Hyssop **
  • Elecampane Root *
  • Ginger *
  • Horehound *
  • Juniper Berries *~
  • Lavender ********
  • Lemon (oil) *
  • Meadowsweet *~
  • Melissa (Lemon Balm) **
  • Nutmeg *
  • Oregano (oil) *
  • Peppermint ********
  • Rosemary ******~
  • Rue *****
  • Sage ********~
  • Tansy *
  • Thyme ****
  • Wormwood *****~
  
  (sampled from 9½ recipes at seven webpages)
  
  The amount of herbs and vinegar both are not always specified - one site says 12 tablespoons of your mixed herbs (excluding the garlic) to 2 quarts vinegar; some suggest adding 3g-1oz of camphor. Obviously, something with rue, camphor (and I'd add wormwood to the list) would not be great for the salad dressing part, but as a diluted external wash or for magickal uses, it's fine. This post might be the most useful of the Google results, as it gives a Four Thieves Oil recipe as well, and the writer's personal experience with the mixtures. This page has multiple recipes, one of which is quite complicated and was therefore not included in the list above. Glycerin is sometimes added as a kind of preservative.
  
  Oh, and as someone who's made red-pepper vinegar, I must tell you it does wonders for clearing the sinuses but needs to be refrigerated due to the natural oils leached from the pepper - it'll go rancid and all disappointing if not kept cold.