Weights and Measures

Are your sins metric, troy or avoirdupois?

Many younger players know little of the imperial system of weights and measures even in Britain. Foreigners tend to know nothing useful while Americans have the additional confusion of a similar system with the same names but different details. On top of that, Gygax did not specifically say whether he was using British or American versions.

Here's a guide for the bewildered based on the use of British (more specifically, English, since Britain was not yet a united kingdom in mediaeval times).

Firstly, some names and abbreviations:

gr = grain (of wheat), a weight
oz = ounce
lb = pound (from libra, the Latin equivalent)
bu = bushel, a volume
ac = acre, an area
yd = yard, a length
ft = foot or feet, ⅓yd
in = inch, 1/12in
tr = troy, a system
av = avoirdupois, another system

Troy and Avoirdupois

Once upon a time there was a very clever person who decided to design a system of weights and measures. He (the chances that a woman would have been allowed to even assist at the time is remote) decided that a cubic foot of water should be defined as 1000oz. That would weigh 62½ lbs.

But, he thought, merchants clearly use two different systems of measurements - dry and liquid. He didn't really want to have to have two systems of barrels and boxes so he struck on an ingenious idea: have two types of pound instead which weigh different amounts but take up the same space. The denser would be for liquids like water, beer, and wine and called "Avoirdupois" and the less dense pound, for wheat and bread, would be the "Troy" pound possibly from Troyes, a town in France. The concept of the troy pound seems to have come over with the Normans and slowly replaced the old Saxon pound which was called the "Tower pound".

Both pounds would be based on the nominal weight of a grain of wheat. A troy pound would be made of 12 ounces of 480gr each, for a total of 5670, but the avoirdupois pound would be divided into 16 ounces of 437½gr each for a round 7000gr total. This set the ratio of troy to avoirdupois pound to 144:175, the same as the ratio of the density of wheat to water.

This meant that a barrel which was stamped "320 lbs" would hold 320 lbs avoirdupois of water or 320lbs troy of wheat.

Unfortunately, because the troy pound was already in wide-spread use, our inventor could not make a cubic foot of wheat weigh 1000 tr.oz, so although the cubic foot of wheat weighs 62½lbs in either system, in the avoirdupois system it is a nice neat 1000oz, in the troy system it is 750oz which is nice, but not as nice and the ratio of troy ounce to avoirdupois ounce is 192:175, different from the pounds' ratio and notice also that although the troy pound is lighter than the avoirdupois pound, the troy ounce is heavier than its counterpoint.

While avoirdupois has survived to the modern day and is what we normally talk about in terms of weight, the troy system was abolished some time ago and survives only in the area of precious metal. So, if you look up the price of gold and find that it is "$1251/oz" that "oz" is a troy ounce, not a normal kitchen-scale ounce.

Sticking to liquid for now, the definition of a cubic foot of water is 1000oz gives us the next fixed point, as an English pint has 20 fluid ounces (fl.oz.) which means:

1cu.ft. water = 50 pints exactly (users of purify food and water, note!)

and since 8 pints make a gallon,

1cu.ft water = 6 gallons and 2 pints.

and since a pint is 20 ounces (1¼lb),

1 gallon water = 10lbs avoirdupois = 160av.oz.

and

1cu.ft water = 62½lbs of water.

and so,

1 gallon wheat = 10lbs troy = 120tr.oz = 8lb 3oz 287½gr avoirdupois

Working backwards,

4½lbs of water (enough to fill a wineskin in the DMG) 0.072cu.ft and so a cubic foot of water represents just under 14 DMG wineskins (13 and 8/9ths)

1.3lbs of water (enough to fill a flask in the DMG) is 0.0208cu.ft and so a cubic foot of water represents just over 48 flasks (48 and 1/13th).

100lbs of water is 10 gallons, which is 1.6cu.ft.

Art: David Wyatt

A 320lb-capacity barrel contains 5.12 cu.ft of water. If it were a cylinder 18" across, it would be 2' 10¾" tall. Too small for a human, but a hobbit or a dwarf might just squeeze in.

Standard rations for a week for one person weigh 20lbs. Technically, that should be troy and if it was, then that represents one peck-sized container and a standard barrel would hold a week's supplies for 16 people (see table below). Iron rations would be much more space-efficient at 42⅔ man-weeks per barrel, although more water would be needed if there is no supply en-route.

Personally, I wouldn't dream of enforcing the difference between avoirdupois and troy in a game, even if the 21% difference is quite substantial. But, it could be done.

The old system generally worked on a binary pattern, so that each named unit is equal to two of the unit below. This obviously made calculations easier but over time some units - e.g., the gallon - proved to be so much more useful than the others that the underlying pattern was forgotten along with many of the under-used units like pottles and chopins.

So the theory is:

2 gills=1 chopin (chiefly in Scotland & France) = 5/8 lb
2 chopin=1 pint (20oz of water) = 1¼lb
2 pints=1 quart = 2½lb
2 quarts=1 pottle = 5lb
2 pottles=1 gallon = 10lbs
2 gallons=1 peck = 20lbs
2 pecks=1 demi-bushel = 40lbs
2 demi-bushels=1 bushel (or firkin of liquid) = 80lbs
2 bushels=1 strike (or kilderkin of liquid) =160lbs
2 strikes=1 barrel or coomb (coomb is technically dry but very rarely used) = 320lbs
2 barrels=1 quarter (or hogshead of liquid) =640lbs
2 quarters=1 pipe (again rarely encountered in dry measure) or butt =1280lbs
2 pipes/butt=1 ton (tun is mostly used for liquid) = 2560lbs

A problem arises here, which is that our unknown systematizer was largely just that - unknown. The simple system he devised was more or less forgotten and certainly not transmitted across the country. As a result, in real life, these units were rarely used so systematically and the derivation of the ton that we have today (in Britain and, by what the French call coincidence, in the metric system) is:

1 ton=20 cwt ("hundred weight")
1cwt=8 stone or 112lbs
1 stone=14lbs
1 ton = 2240lbs

In addition, all of the big above list were based off the gallon and that also varied across the country, each variation taking the other units with it. This version of the system made allowances for crating and packing. So a hundred-weight (cwt) supposedly included 12lbs of packing allowance and a ton 240lbs, leaving 2000lbs for the actual goods. In America this allowance was discarded and weights simply given in terms of delivered goods, and so their ton is this "short" ton of 2000lbs.

Anyway, the practical upshot of all this is that the weight of any of these units depends greatly on the contents. Clearly, if one piles grain into a bushel measure and levels it off there is a great deal less air in the resulting container than if one did the same thing with apples, let alone the issue of the different densities of an individual grain or apple. Meanwhile, the local definition of the bushel varied frequently.

Thus bushels vary in weight:
Wheat or rye: 56lbs is the most common size encountered, followed by 64lbs
Barley: 48lbs
Oats: 38lbs

Modern bushels are mostly encountered in the US where the wheat bushel has been rounded to 60lbs.

Notice that none of these bushel weights is very close to the theoretical weight of 65 and 29/35 lbs that the avoirdupois:troy ratio would suggest. Which tells you all you need to know about how successful the would-be systematizer was.

Since bread was made from wheat, old sources tend to talk about a 1lb loaf meaning one troy pound. This means that a pound of bread provided somewhere in the region of 920 kcals, not the 1120 that one might expect if using avoirdupois weights.

Small Weights
The pound avoirdupois was sub-divided:

1lb= 16oz = 256 drams
1oz=16drams = 32 quarters
1dram=4 quarters
1 quarter = 1/1024 lb

The pound troy was sub-divided:

1lb = 12oz
1oz = 8 drams
1 dram = 3 scruples
1 scruple = 20 grains
1 grain = 1/5760 lb

However, since the troy pound came to be the pound of silver and silver was the coinage of the realm, it could also be divided so:

1oz = 1 shilling
1 shilling/oz = 12 pennyweight
1 pennyweight = 24 grains
£1 = 20 shillings = 240 pennyweights

and this is the origin of the slogan on all English banknotes "I promise to pay the bearer on demand the sum of ..." followed by the face value of the note. It used to be that a £50 note was literally worth fifty troy pounds of silver and one could exchange it at the Bank of England. This ended in the late 1700's but the text remains essentially as a hollow endorsement of the government's non-existent commitment to financial prudence.

Distances
A foot is 12" and an inch is now defined as being exactly 127/5000th of a metre, for what that's worth.

3 feet are a yard, so a tank with a capacity of one cubic yard holds 1350 pints weighing 1687½lbs.

2yds is a fathom.

5½yds is a pole or perch.

22yds is a chain.

220 yards (40 poles) is a furlong. Dividing the furlong into 200 units gives you a metre.

8 furlongs is a mile.

3 miles is a league.

Areas
1 furlong by a chain is an acre of 4840sq.yds. or 43560 sq.ft

One inch of rain on an acre thus represents 3630cu.ft of water, which is 226,875lbs of water, or 2,2687½ gallons, or 709 barrels (minus half a gallon).

1 furlong by a furlong is 10 acres

640 acres is a square mile.

30 acres is a virgate.

4 virgates (120ac) is a hide.

100 hides is a "hundred". However, the word "hundred" actually originally mean 120 and in some places this held in the definition of the hundred of land while in other places the hundred was chopped up without changing the name. Consequently, references to "hundreds" of land in old sources can refer to quite widely differing amounts of actual land. In any case, the original concept seems to have been that each hide would be responsible for providing a warrior to the king's warband.

I think this has been abolished except in parts of Lincolnshire.

Fatigue and the Nymph

'Nuff said!

AD&D doesn't have obvious fatigue rules. Which is to say that it has fatigue rules but they're almost unknown as such. The rule in question is under forced movement on page 49 of the Dungeon Masters Guide. The system is fairly simple and has its obligatory "that's just wrong" and "I'm not sure what that means" passages too, for that genuine 1e experience.

The system is this: one can move the normal allowance (whether the DMG's odd-ball hold-over system from OD&D, or the PHB's nicely abstracted system) without penalty.

After that, things get a bit weird and the word "hours" appears in the rules where I think it probably shouldn't and certainly doesn't make sense with the worked example in the text. So, this is my reconstruction of the rule:

1. For a forced march of 10-30% over normal movement, there is a multiplier of 1.
2. For a forced march of 40-60%, the multiplier is 2.
3. For a forced march of 70% or more the multiplier is 3.

The amount of forced march (10-100%) is multiplied by the given value and that is the amount of travel time that is lost on the next day due to resting.

So, a character on horseback (24") has a normal movement allowance of 48 miles in the PHB system. Travelling 55 miles in a day counts as 20% forced march and therefore 20% of the following day is lost to rest, taking that day's base movement down to 38 miles.

If the same horse rider moves 90miles in a day, which is 90% over, then 3x90%=270% of a days travel is lost. In other words, the horse must rest for two days and on the third day will only manage 30% of normal movement, or about 15 miles.

All this resting can be ignored and characters can push themselves, and/or their mounts onward beyond 200% of normal movement. At which point each 10% (or part thereof) extra movement carries a 10% chance, cumulative, of killing "beasts of burden" and reduces the hit dice or level of creatures by 1 until they too drop dead.

The loss of hit dice/levels lasts until the character has rested for 8 hours per 10% movement over 200%.

For an example: a 9th level dwarven fighter with 6" movement can travel (using the simpler PHB system) 12 miles in a day. But there is a battle to get to, and so she marches on doing 20 miles instead (70% over normal). She should rest for more than two days, but can not due to the fact that there's a battle on. Forced to fight, she is only able to contribute as a 2nd level fighter.

That's the whole system and some obvious points are left to the DM. For example:

1. Can characters rest for some time and recover some levels? I would say yes, so if the dwarven lady was able to rest for a day she would get 4 levels back (at 8hrs per level).
2. What counts as a "beast of burden"? I take it to mean normal animals such as horses and mules while, for example, a paladin's warhorse would count as a creature with hit dice. I think that it also covers 0-level characters.
3. How does the loss of hit dice/levels interact with hp? Personally, I would tend towards counting each lost level as loss of hit points at random where applicable. Thus, a 12th level fighter losing 2 levels to fatigue would lose only 6hp but our dwarven lady would lose 7d10hp (I would specifically not add CON modifiers to this) and a thief would suffer damage using d6.
4. How does lack of rest interact with spell memorization? Actually, I think this is fairly easy to guess; see below.
5. What's the effect of fatigue on the rider of a horse or other animal? I've no idea on this one but I'm going to try ½ for now and see.

Well, quite

Who Cares?
I'm generally against systematizing any more than is needed - been there, researched the rules for making t-shirts - but fatigue is something that is a common plot device or concern in fiction, and the ability of characters to press on beyond normal limits is something that marks them out as heroes.

Let's get down to generics
Well, this is all nice and good for forced marches; can we use it more generally? I think so. The overall system can be abstracted to:

1. There is a limit to what normal people can do in some base time period.
2. There are increments over this which anyone can force themselves to perform which incur what I'm going to call "fatigue points".
3. Once 10 points have accumulated, beasts of burden have a % chance of dying equal to 10 x fatigue each time a new fatigue point beyond 10 is incurred (so 10% at the 11th point, 20% at 12 etc.).
4. For each point over 10, characters subtract their one from their level (and, I think, suffer hp damage as appropriate).
5. Each fatigue point up to 10 requires a number of base time periods times 1, 2, or 3 depending on the maximum total number of points a character has reached since they were last at 0.
6. Recovery time for points over 10 is 8 hours per point.
7. Spell memorization is impossible while fatigue points are above zero.
8. Heal removes all fatigue points.
9. Cure spells and potions remove one point per d8 of curing done.
10. Natural healing does not start until fp=0.

For example, characters are normally required to rest a turn in every hour. We could say that pressing on without such a rest counts as one fatigue step per period skipped. For 1-3 such steps the characters have to rest for one hour per fatigue step, for 4-6, two hours, and for 7-10 three hours per step.

So, a party exploring a dungeon is in a hurry and take no breaks for 10 hours. At this point they have 10 fatigue points and each of these will require 3 hours to remove. But at this point they find the lair of a group of drow and enter combat. Rest is also normally required after a combat but the DM rolls a wandering owlbear attracted by the noise and the party are unable to take that rest and so incur another fatigue point, taking them to 11. Each character who fights the owlbear loses one level worth of hit points and performs at one level below normal.

Blocking up the door of an empty room to rest up, the party finally takes a break. The members who did not fight the owlbear will require 30 hours of rest to get back to 0 fatigue, the ones who did will require an additional 8hrs.

Various spells and magic items may modify these effects is more or less obvious ways.

You mentioned "Nymphs". Where are the nymphs?

Monster Name: Ice Nymph

Frequency: Rare
No. Appearing: 1
Armour Class: 6 (10+4 for dex)
Move: 12" (see below)
Hit Dice: 3
% in lair: 10%
Treasure Type: 1-4 Jewels 50%, X
No. Of Attacks: 0
Special Attacks: Fascinate, Stunning
Special Defenses: Immune to cold
Magic Resistance: 50% (12)
Intelligence: High
Alignment: CN(E)
Size: M
Psionics: None
Level/xp: V/330+4/hp

The ice nymph is a nature spirit of water which has been frozen for a long time (i.e, many years). Their normally warm and beneficent nature has become cold and brittle like the water they were born from and they are generally much more hostile than their MM counterparts.

Additionally, their appearance is different and although lively, and lithe, their flesh has taken on the appearance almost of a corpse with blue lips and pale grey/blue skin. Eyes and hair remain as animated and beautiful as ever, however, and it is unlikely that they could be mistaken for undead at any distance under 30' or so.

They share their sister's ability to use dimension door once per day and can also move over ice or snow as if it were dry, firm soil, leaving not even a foot print.

Their druidic spells are normally: 1st) Faerie fire, Invisibility to animals, Predict weather, Speak with animals; 2nd) Cause light wounds, Chill metal; 3rd) Hold animal, Protection from fire; 4th) Quench fire.

While cold-based attacks have no effect on ice nymphs, fire-based ones do an extra hit point per dice of damage.

The change in their appearance has modified the effect of their beauty. Firstly, looking at one causes only a fascination effect whereby those viewing the nymph must save versus spells (with wisdom bonus/penalty, and an additional +4 for females) or be drawn to pursue the nymph for an embrace.

The nymph may give orders to fascinated males by promising various things but each such promise delayed or broken allows another saving throw with a modifier of +1 for each broken promise. Orders which directly harm the victim or their friends or which normally would be against their alignment will additionally allow a saving throw before the order is carried out. Females can not be so manipulated but are otherwise affected by the nymph's aura.

Should the nymph feel particularly threatened, she may disrobe completely. Doing so has the effect of power word stun on all males within 12" on first laying eyes on her. Females are affected but receive a saving throw.

Ice nymphs are generally haughty and arrogant, even those which are not evil, and are loathe to stoop to disrobing and will only do it very reluctantly and usually to take the opportunity to flee. Naturally, they can not be tracked while in their natural environment.

If someone actually manages to get a hold of an ice nymph, their naked touch will cause 1hp of damage per round to both a warm-blooded holder and to the nymph; increasing at the DM's discretion if the contact is extensive. If the grabber is cold-blooded then double damage is only incurred by them and none to the nymph. Undead may handle the nymph without injury to either.

Ice nymphs are only encountered on ice or snowfields and are usually alone. However, 60% (1-12 on d20) of nymphs have 1d4 frost giants as fascinated bodyguards back in her lair (were their treasure will be added to hers), 15% (13-15) have 2d8 wolves who will be nearby, 10% (16-17) have 1-2 polar bears who can be ridden or harnessed to a sledge for transport, and 5% (18) can summon an ice para-elemental (MMII p98) once per week.

A (rare) friendly encounter with an ice nymph may take the form of a distant voice calling out through a storm to guide a lost party to safety. No matter what the weather, an ice nymph's voice always carries as if it were the dead of the stillest night.

A neutral encounter with an ice nymph will usually involve similar use of their voices to play tricks on a party, the severity of which will depend on the exact reaction roll but will not directly kill them.

A typical hostile encounter with an ice nymph will take place when a lone male is out in deep snow which hampers his movement. If there is more than one man the nymph will probably sow discontent. The victim will then be tempted to follow through the snow, either until they collapse from fatigue or encounter the nymph's companions.

Movement through deep snow is very hard work and movement rates should be reduced to ⅓ of normal, to a minimum of 1". Each half hour of such movement counts as one fatigue point as above (with half an hour as the base time period).

In addition, characters who are dressed inappropriately (and removing bulky and warm clothing will be one of the nymph's first suggestions) will suffer additional penalties: firstly, actually taking rest will not help reduce fatigue unless they can find warmth somehow, and secondly, they will receive an additional fatigue point for each one which would normally be incurred.

Don't click here if you're not Australian!

Bloody Encumbrance

A slight detour before the final post in this set of introductory notes to look at encumbrance in AD&D.

Encumbrance is probably the most old-school mechanic in the game. Modern games have, like most AD&D DMs, tried to look for various simpler ways to handle encumbrance and many have simply given up on the whole topic and scrapped it, replacing it with guidelines like "just be reasonable". There's a few problems with this in AD&D. Primarily they are to do with the game's assumptions.

The glamour of low-level adventuring

AD&D is, as previously mentioned, frequently about resource management, at least at the system level. As the game progresses and the character increase in level the nature of the resources change as part of a general movement away from realism and into the fantastic.

For low level characters one of the things that they are limited by is carrying capacity. Take away this restriction and you make one aspect of low-level play a lot easier. You also negate one of the advantages of high strength scores.

So, my advice is to use the system as printed and see how it goes. Obviously, this assumes that you know what the system is, which is just a case of reading a section in the rule books, right?

Wrong
Encumbrance has several aspects in AD&D: weight limits, bulk, and movement limits. These three factors feed into the character's weight limit, dexterity, and movement rate respectively.

A character can be unencumbered, moderately encumbered, encumbered, or overloaded (these terms are not consistently used in the rules). In game the effects of the first two are fairly clear; but the others are not defined anywhere in the rules.

• Unencumbered: normal action; no effect.
• Heavy: the character's dexterity bonuses for surprise and missile fire do not apply, although any armour class bonus does. Note that any penalties still apply. Movement is reduced by 3" from base.
• Loaded: not only do bonuses not apply, but the character is "slowed" but no rules are given about what this means. Movement is reduced by 6" from base.
• Maximum/encumbered: "slowed greatly". This is also not defined (edit: there is a +2 to-hit modifier, DMG p67),.  Movement is reduced by 9" from base.

Over the years, I've tried many definitions of "slowed" and "slowed greatly". At the moment my suggestion is that they are used as individual initiative modifiers of -1 and -2, with negative numbers being possible. I'll look at this more in the post about initiative.

1. Weight
"Loose" items only relate to weight, but shields also add bulk, and armour adds both armour and movement limits. Magical armour introduces probably the most well known of the rules' self-contradictions.

Here's a table based on strength of what each of these means in terms of weight limits (counted in gp values; 1gp=1/10th lb):

STR	Unencumbered	Moderately	Encumbered	Overloaded
3	263	525	788	1050
4–5	288	575	863	1150
6–7	313	625	938	1250
8–9	350	700	1050	1400
10–11	350	700	1050	1400
12–13	375	750	1125	1500
14–15	400	800	1200	1600
16	438	875	1313	1750
17	475	950	1425	1900
18	538	1075	1613	2150
18/01–50	600	1200	1800	2400
18/51–75	663	1325	1988	2650
18/76–90	725	1450	2175	2900
18/91–99	850	1700	2550	3400
18/00	1100	2200	3300	4400
19	1475	2950	4425	5900
20	1600	3200	4800	6400
21	1850	3700	5550	7400
22	2225	4450	6675	8900
23	2600	5200	7800	10400
24	3350	6700	10050	13400
25	4100	8200	12300	16400

Thus, an average strength person (STR 11) can carry 35lbs (350gp) weight or less with no effects and can not carry more than 140lbs/1400gp. An 18/00 fighter can carry 110lbs without effect, and has a maximum carrying capacity of 440lbs.

2. Bulk

Armour and some shields are rated for bulk as either non-, fairly, or bulky. Basically, these set the character's minimum encumbrance regardless of weight carried as unencumbered, moderately encumbered, or heavily encumbered. Thus an average strength person carrying 500gp and wearing bulky armour is treated as being heavily encumbered rather than moderately. If carrying 1200gp they are still counted as being overloaded.

3. Base Move Rate
Each type of armour has in addition a maximum movement rate stated in inches. This is a slight tricky rule as it's not clear, for example, whether a character with a base 15" move is treated in the same way as a character with a 12" move rate. Adding to the complication is the question of what the demi-humans' move rates are since the rates given in the monster manual seem to allow for armour already.

In the dungeon this is no great issue as underground movement rates are so slow that the average dead dog could keep them up indefinitely; the limiting factor there is stealth rather than actual movement ability and the heavier armours' low move rates can be rationalized as reflecting the difficulty of moving quietly in them (or not - you don't have to rationalize anything if you don't want to). Over long distances outdoors, it's probably worth ignoring the question although you could reduce dwarf movement by 25% and halfling/gnome by 50% if you feel that the human rates are too unrealistic (you should also reduce weights of clothes, shields and armours by the same amount if you do this). I would leave elves at 12" movement.

It's Magic. Or is it?
And now the contradiction. The DMG tells us that magical armour is half the weight of non-magical armour and one step better maximum movement (p28) and that it is weightless and imposes no movement limitation at all (p164). Which is right? The DM can pick, but I generally use the difference between chainmail and elfin chainmail as the basis so that magical armour is:

• Half the weight
• One step less bulky
• One step less restrictive to movement.

Magical shields weigh the same as non-magical shields, although you might want to overrule that either for particular shields or for all. Note that a large shield is bulky and I'd certainly reduce that to fairly-bulky for magical ones.

Magical weapons have no special weight or handling rules by default.

So, in summary, a human fighter with STR-17 wearing magical platemail and carrying a large shield and bastard sword, backpack with change of clothes a tinderbox and half a dozen torches, 50' of rope, a flagon of beer (1 quart), and a sack with 120 gold pieces is carrying a total weight of 902gp. This would make him moderately encumbered with a movement of 9" but the large shield is bulky and makes him encumbered, with a move rate of 6" and the penalty of being "slowed".

Generally, speaking, large shields are not designed for mobility, although I would recommend discarding the bulk penalty when used on horseback as per the Normans (replacing that penalty with a restriction on which flank the shield protects).

That's plenty on encumbrance for now except to point out that when using the encumbrance rules there are armours which simply are inferior in all ways, including cost. However, not every campaign will allow all armour types to be available and still less so individual towns and villages within a campaign.

Onwards - to initiative via surprise!