How do you know how invested a spike is?

[Nightstar The Bright]

Quote

The woman fell silent, and the assistant washed off the bloodied spike and handed it to Labcoat, who promptly placed it in a solution attached to a device and examined it.

“Roughly five percent Invested,” she reported to Entrone. “And as you can see, the subject is still alive. We’ve essentially excised a piece of the soul and stored it in the metal.”

Like the title states, how did the scientist know that the spike was 5% invested. Is there a way to read the investiture in spikes?

[alder24]

8 minutes ago, Nightstar The Bright said:

Like the title states, how did the scientist know that the spike was 5% invested. Is there a way to read the investiture in spikes?

We don't know. Probably from experience. They've done this before and know it takes 20-30 people to fully invest a spike like this, thus a single person can invest it only by around 5%.

But there are ways in Cosmere to measure investiture, Cosmere spoilers:

Spoiler

they can use White Sand to measure it. It was used in RoW that way and the Set is working for Autonomy, they have Trellium so why not White Sand too? RoW ch 84:

Quote

“I will,” she said. “But Lady of Wishes, I’m running into another problem. I need a way to measure the strength of Stormlight in a gemstone.”
Raboniel didn’t press for details. “There is sand that does this,” she said.
“Sand?”
“It is black naturally, but turns white in the presence of Stormlight. It can, therefore, be used to measure the strength of Investiture—the more powerful the source of power nearby, the quicker the sand changes. I will get some for you.”

 

Spoiler

Questioner

Mraize's Basement Emporium. Is that more like a trophy room or a "In case of emergencies" room?

Multiple people

Or a bank vault?

Or a weapon's vault?

Or both?

Brandon Sanderson

So, yes...

I mean, he can't use the aether, right? ...He can't use the aether, he doesn't have an aether. But the sand, the sand does stuff. So a handful of sand is a really useful amount of sand to have if you're not a sandmaster. Because sand reacts to Investiture. So if you let it fade and you take it somewhere, as soon as Investiture goes kinetic, it'll turn white again. So you'll be able to use it to tell who's using Inve-- it works just like a Seeker, like bronze pulses...

So having white sand, having sand around is really good. If you can keep the little beasties that are growing on the sand around, they will react to basically the Investiture equivalent of radiation. So that's handy.

Emerald City Comic Con 2018 (March 1, 2018)

 

[Nightstar The Bright]

2 hours ago, alder24 said:

We don't know. Probably from experience. They've done this before and know it takes 20-30 people to fully invest a spike like this, thus a single person can invest it only by around 5%.

But why would she need to examine the spike? I imagine that there wouldn’t be a need to examine the spike if she already knew how invested it was. It is more likely that something about it ‘changes’, which you can see/read.

 

2 hours ago, alder24 said:

But there are ways in Cosmere to measure investiture, Cosmere spoilers:

Ah yes I had forgotten about White Sand.

[Trusk'our he/him]

4 hours ago, Nightstar The Bright said:

Like the title states, how did the scientist know that the spike was 5% invested. Is there a way to read the investiture in spikes?

I believe that it's possible the device they used was the same type that Wax used to tell that Harmonium and Trellium were Godmetals- they gave off a certain wavelength when an electric current was run through them (I think. It's been a bit since I've read the book and I don't have it on me right now).

Perhaps the more Investiture is in a metal, the more light is emitted when an electric current flows through it, which by extension could be measured.

This is how I imagined them measuring the Investiture of the spikes.

[Nightstar The Bright]

27 minutes ago, Trusk'our said:

I believe that it's possible the device they used was the same type that Wax used to tell that Harmonium and Trellium were Godmetals- they gave off a certain wavelength when an electric current was run through them (I think. It's been a bit since I've read the book and I don't have it on me right now).

I thought that Wax and friends were wrong in assuming that a full spectrum meant a god metal, and god metals just happened to have full spectrums. But I suppose it’s possible the Set use this to tell how invested a spike is. 

[Duxredux he/him]

I have two metrics that they can use to directly measure the Investiture in a Hemalurgic spike, since they obviously have access to normally charged, partially charged, and uncharged spikes.

Option 1: comparison of Steelsight line thickness. Fainter line means more Investiture, keep spiking until it matches the one charged through conventional methods.

Option 2: repulsive strength of Trellium against the Hemalurgic spikes. If I remember right, the normal spikes held by the cycle that Marasi killed were repulsed by the Trellium spike. Presumably this scales with the strength of Investiture in the spike or at least follows a curve that they can use to compare a normally charged Hemalurgic spike with the progressively charged spike.

Either seems plausible, the Trellium method allowing for a more rigorous methodology.