Once in a Blue Moon

Here again lies a cliche I use frequently in conversation.  But how often does a “blue moon” really occur?  I mean it to occur regularly, but not often.  Where did this come from and what does it really mean?  Thanks to the wonder of internet research, which can never be wrong, I can tell you exactly what it means.

 Frequency

A full moon occurs approximately once per month, but the solar calendar year contains eleven more days than the lunar calendar year.  These days accumulate, and therefore about every two to three years, there is an “extra” full moon.  The term “blue” moon comes from folklore–here is a couple of possibilities:

• The word “belewe” had a double meaning in Old English; either the color blue or “to betray”.  In determining the dates for Lent and Easter, clergy use the lunar calendar and it is thought that when the extra moon came too early, it was the “betrayer” moon so the Lent moon could occur at its predicted time.
• The Farmer’s Almanac defined a blue moon as an extra full moon that occurred in a season.  If that season had four full moons, then the third full moon was called a “blue moon”.

Appearance

The most literal meaning of blue moon is when the moon appears unusually bluish to the observer.  This can happen when dust particles of the correct diameter (slightly larger than the wavelength of red light,  at approximately 700nm) exist in the atmosphere without many particles of differing size.  Occasionally volcanic eruption can cause such a moon, as happened after the eruption of Krakatoa in 1883 which caused the moon to appear more blue for almost two years.

Most ash and dust clouds thrown into the atmosphere by fires and storms have particles of many different sizes, many smaller than one micron, which causes the moon to have a red appearance.  Red appearing moons appear much more commonly than blue.  This lends credence to the terminology and tradition of a blue moon being an infrequent event.

There's One!

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Not Worth His Salt

I wondered once too often about the origin of this phrase.  As I wrote it today, I decided to do something about it.  The phrase “worth one’s salt” began with the ancient Romans, perhaps as early as 900 B.C.  During that time, soldiers were paid for work in “salarium”, an allowance for the purchase of salt.  Salt was a hard-to-find commodity in the ancient world and regarded as good for health.  The literal translation of the word “soldier” from that era is “one who is paid in salt”.

Look at the Latin word “salarium” which means “pay”.  This was shortened as it appeared in English to salary.  When you say that someone is “worth their salt” it means that they are worth the wages that they earn.

 

Dead as a Doornail

I have used this phrase countless times either in the above iteration or as “deader than a doornail”.  But one day it crossed my mind as strange.  All nails are dead, inanimate objects, why should doornails be any more so?  Is the intention referring to death by doornail?  A little research has revealed, no.

History

This is quite an old term, actually.  It is referenced in print as early as 1350, and Shakespeare used the term in King Henry VI, Part 2, 1592:

Brave thee! ay, by the best blood that ever was broached, and beard thee too.  Look on me well: I have eat no meat these five days; yet, come thou and thy five men, and if I do not leave you all as dead as a doornail, I pray God I may never eat grass more.

A "dead nail" with its tip clenched back into the wood, a common way to fasten door hinges to keep them from working loose.

I learned from the Appalachian Blacksmiths Association that in the day of forged or cut nails, manufacture was quite labor-intensive.  Therefore nails were reused when possible.  The tips of the large-headed nails used in hingeing doors (remember, this is before the usage of wood screws, for which a satisfactory lathe to manufacture was not invented until the late 1700’s) were turned back into the wood as shown in the rendering at the left, a procedure called “clenching”.  Nails were so scarce and expensive in pre-1850 America that people would burn down dilapidated structures just to sift the ashes to recover nails.  Clenched nails like the one shown above, however, were too bent to be reused, and were christened “dead nails” by the construction industry.  Hence the term, “dead as a doornail”.  This research led me to another question.  Why is the term “penny” used to describe the size of a nail?  It is its weight in pennies or some equivalent?  Again, no:

10d

The term “penny” is still used when referring to a nail’s size.  In the 1600’s when it is believed this term came into use, the English monetary unit was the Pound Sterling (£) which was divided into shillings and pence.  The cost of 100 nails in 1600’s pence is how nail sizes are described to this day.  For example, 100 small nails, selling for 4 pence were called 4d nails (4d is the abbreviation for 4 pence and is still used to describe a 4-penny nail).  100 larger nails sold for 10 pence are 10d nails, and so on.  The price of nails was apparently near constant for a long period of time, and thus led to standard sizes.  Nail recovery has been all but eliminated with the use of modern wire nails.

Wire vs. Cut

Forged nails are square, each side being tapered to the tip.  Cut nails were quicker to manufacture, and were characterized by two tapered sides and two parallel sides, where they were sheared from steel plate.  A second machine forms the head of a cut nail.  Wire nails are round.  Steel wire of varying sizes is fed through a machine that grips the wire, cuts it, chisels the point, and forms the head all in one operation, churning out thousands of nails per minute.  Wire nails are cheaper to produce, but the cut nail has about four times the holding power of its round cousin.  You now know more about nails than you ever cared to.