I think I did not post them when I originally designed them, so I am posting them now. 
I revewed some of the effects in light of better understanding of some things and corrected a few calculation mistakes.
if you want to comment, maybe it would be better if you did it in the original thread instead of here, in order not to contaminate Gremlin44's thread The thread: https://forum.atlas-games.com/t/mechanica-of-heron-can-this-be-done/5388/1
WONDERS OF ALEXANDRIA: MECHANICA OF HERON
The Mechanica deals with stuff that seems to look mundane as far as I can see. this "magic" is about making magical stuff out of what was pure physics work. This entry uses Igneus, a 3rd century Mechanician from Alexandria as the creator of the items. He had a lab total of around +20 (easily achieved for a mechanician) and up to +24 when he is older and more experienced. Igneus had a penchant for fire and heat effects. He would have made good friends with a classical Flambeau magus.
Some sample items that Igneus and his helpers would have created.
Lightbringer
Effectively, a POF wand
CrIg35
Penetration: 22, 12 uses/day.
Range: Voice. Duration: Momentary. Target: Individual.
A (rather bulky) brass baton with the head of a dragon at one extreme. The dragon head has its mouth open, ruby eyes, and is profusely decorated. The baton shots jets of flame using an improved naphtha mix. It deals +15 damage to the target at voice range. After running out of charges, the baton needs to be recharged before it can be used again. This is a time consuming operation, but not something overly complicated.
Igneus created this item because his patron demanded him to accompany him in an upcoming military campaign. Being a total toad in close combat, Igneus decided he would need some kind of combat capabilities to survive. The best way to keep enemies at bay is playing with their fear of “the mighty wizard” (and roast them if they get too near). Igneus had to experiment to create this item, and the result is that the results tend to be so spectacular that he attracts the attention of everybody at Voice range each time he uses Lightbringer (minor flaw).
B10; +2 voice; Penetration +11, uses/day +4
Magnitude: 7
Difficulty Level: 24 (7*3 +3 easily transportable)
Cost: 8 pounds
Alter Mechanica: Lightbringer
Penetration 12, 12 uses/day.
Some years after the military campaign that was so scary for Igneus, he decides to go on an expedition (men never learn…). Carrying a Baton all day long is not something he wants, especially one that is so easy to spot. Igneus decides to alter Lightbringer and turn it into an armband. The final design looks like an armband that links a small deposit of naphtha located in Igneus’ back to a shooting overture just under his wrist. The mechanism operates by pulling a string attacked to his fingers with a strong movement of his wrist. The conversion works well, but the effect still has the flaw of attracting everybody0s attention at voice range when activated.
Inspiration for the second potential design form of the Lightbringer: Image in Sub Rosa #3 p.14 (Societas Flambonis)
CrIg30. Hand sized (+6) and Penetration 12, since the downsizing of the shooting mechanism has limited the impetus of the flames. The item requires to have a Base effect of difficulty 18 (6th magnitude spell effect) to accommodate the smaller size with the same lab total. This heavily reduces the penetration.
Flames of Alexandria
Braziers of eternal flame without fuel. 2 of them because it looks cooler (cosmetic effect)
CrIg24
Pen: 0, Constant effect.
Range: Pers. Duration: Sun. Target: Ind.
The Flames of Alexandria are a pair of braziers on a tripod that have an eternal flame without fuel. This is not obvious at first sight, since the height of the tripod means that the braziers are above the eye level of the observer. They illuminate a whole room with a light equivalent to a cloudy day. Igneus built 2 pairs of these braziers, 2 for himself and 2 for his patron (2 seasons in total). A pair of them can be found still working in the council chamber of Castra Solis, but nobody has bothered investigating them. They are just assumed to be Hermetic by casual observers.
Base 4, +2 Sun, +2 Room; +1 2 uses/day, +3 environmental trigger
Magnitude 5.
Difficulty Level: 15
Cost: 5 pounds for the pair
Crown of Light
Aura of Rightful Authority crown.
ReMe25
Pen: 0, 1 use/day
Range: Touch. Duration: Sun. Target: Room. 1 use/day
The crown of light is a crown that uses mirrors, transparent jewels and reflective gold and silver to project the light of a candle around the wearer in an awe-inspiring display. The wearer appears to shine and appear god-like, and people tend to be willing to follow his lead, assuming him to be their natural superior. The crown also prevents the wearer from moving fast, since the candle and mirror displays need to be moved with care, so he must act regally whether he likes it or not. After each use, the mirrors and jewels become dirty with smoke and need to be cleansed, preventing repeated use of the item. Being designed for awe inspiring entries and processions, this is not a major problem. The candle is designed to last quite a long time, and the effect remains even if the candle is consumed and the light recedes since the awesomeness is still in the mind of the observers.
Base 5, +1 Touch, +1 Sun, +2 Room; 1 use/day,
Magnitude 5.
Difficulty level: 15 (5*3 +3 Easily transportable -3 Additional time to use)
Cost: 5 pounds
Focus of Helios
Archimede's burning mirror
MuIg25
Pen: 0, unlimited uses/day
Range: Voice. Duration: Momentary. Target: Part.
This huge enchanted mirror gathers and concentrates the sun's light and heat into a narrow beam, which can be used to ignite distant objects. If the item’ user succeeds on his Aiming roll, the target becomes extremely hot and may ignite flammable objects, like ships. After each use, the mirror needs to be recalibrated and focused again. The Focus of Helios can only be used in clear days; fortunately, those are quite common in the Mediterranean. On those clear days, Voice range can go well beyond a mile.
Base 4, +2 Voice, +1 Part; +10 uses/day.
Magnitude 5.
Difficulty level: 9 (5*3 -3 Additional time to use, -3 wagon sized)
Cost: 3 pounds
Wings of Ikaros
Wings of Soaring Wind
CrAu37
Pen: 0, 3 uses/day
Range: Touch. Duration: Conc. Target: Ind.
A pair of wings made of wax, brass, wood and eagle feathers attached to a rigid leather jerkin. It allows the wearer to fly, even if it is a tiring experience to do so (you need to flap the wings with your arms), and not overly comfortable. The wings have Daedalos’ warning to Ikaros written in the jerkin’s chest, as a reminder to the user about the dangers of hubris. Igneus designed it to accommodate the baton form of Lightbringer in a special compartment in the belly to be able to “play dragon” and shot jets of flame to the ground while making low flights. It is extremely vulnerable when doing so, though (risk of crashing and of being shot down), so he tends to avoid doing that. To fly the Wings, the wearer uses Athletics.
Base 5, +1 Touch, +1 Conc, +2 highly unnatural, +1 Rego req.; +5 item maintains concentration, +2 uses/day
Magnitude 8.
Difficulty level: 24
Cost: 8 pounds
Fireplace of Wonders
MuIg20
Pen: 0, 1 use/day
Range: Touch. Duration: Conc. Target: Ind.
A big fireplace that can change the color and shape of the flames in it by an ingenious system of wind pipes (lots of them) and powders that can be blown into the steady fire, shaping it in any form the controller (using a series of levers) wants. It tends to be used to tell stories. Given its extreme flexibility it has been used even to draw maps. The fireplace is extremely useful to make impressive fire displays and to illustrate moods or stories in the area. It is especially popular with children and with visitors during troupe representations. Without constant maintenance, the wind pipes that manipulate the fire become chocked with soot and the item stops working, so it might still be laying in a townhouse in Alexandria or the Middle East without its current proprietors knowing they have such a marvel at home.
Base 4, +1 Touch, +1 Conc. +1 Complexity (mutable display); +5 Item maintains concentration.
Magnitude 4.
Difficulty level: 6 (4*3 -3 cart size -3 Additional time to use).
Cost: 2 pounds
Breath of Aeolus
Structure chamber of spring breezes
CrAu24
Pen: 0, Constant use.
Range: Touch. Duration: Sun. Target: Structure.
A big face of a blowing titan (Aeolus) set in a wall of the underground area of the patron of Igneus. An ingenious water system behind the statue keeps cooling the air and keeps it cycling, so it does not become stagnant.
(Base 1, +1 Touch, +2 Sun, +3 Structure, +1 unnatural; +1 uses/day, +3 environmental trigger
Magnitude 5.
Difficulty level: 12 (5*3 -3 cart size)
Cost: 4 pounds
Bathtub of Cleopatra
ReAq7
Pen: 0, 24 uses/day
Range: Touch. Duration: Instant. Target: Individual.
This system regulates the temperature of a big bathtub full of water (or another liquid, like milk) to a nice warm state or the temperature that the user wishes. It does this using a series of canalizations linked with a boiling water cauldron and other canalizations linked with a cold water source. The amount of heat can be regulated by a system of levers and shutters that can be operated from within the tube itself. After a few changes of temperature the boiling water source tends to become exhausted and needs to be left to cool before using it again. The item needs to be prepared before use, since the water caudron needs to be brought to boiling temperature.
This was one of the first projects made by Igneus. These bathtubs were fairly popular among the nobility of Alexandria, and the apprentice Mechanicians created a lot of them to practice their art and get easy income and patronage. A few of them might still lay around abandone in several parts of the old Hellenistic area of influence.
Base 1, +1 touch; +5 uses/day
Magnitude 2.
Difficulty level: 3 (2*3 -3 cart Sized -3 Additional time to use; minimum difficulty is 3 anyway)
Cost: 1 pound