1840 Indian Rebirth

Chapter 136 [Metal Detector]

The convenience of circulation is indeed one of the reasons. Compared with gold coins, silver coins and copper coins are undoubtedly more suitable for daily use.

But this is not the main reason. The reason why the horse post needs more silver coins is mainly to realize an invention.

With a thousand brand-new Browning revolvers and guerrilla warfare formulas taught by the horse post, Chavez left Sleeping Bear City...

The horse whistle brought the silver coins, first found a few bottles of nitric acid, and purified the silver in the silver coins.

The silver content of these Spanish silver dollars is not high, only about 90.00%.Silver coins are generally not pure silver, and often need to add some other metals, mainly to improve hardness and make them more durable.

Then he gave the purified silver to a blacksmith and told him to make the silver into silver wire and some small parts.

With these silver wires and parts, Mashao can officially launch his invention - the metal detector.

Strictly speaking, he has already invented the metal detector. After all, the principle of this thing is not complicated. It is mainly an eddy current effect, and it is still the content of high school physics. Of course he can make it.

But the problem is that the metal detector he invented before is too poor.In the beginning, even the metal could only respond if it was pasted on it.

It may be that the design is not good enough, or it may be that his manual level is not good enough.

Of course, it is more likely that the front-end technology is not enough. The battery is an improved voltaic stack, the voltage is not stable enough, and the indicator device is a small fan, which is not very intuitive.

All in all, no matter how he improves, the performance of the metal detector is still not ideal.So in the end he decided to try to replace all the wires with silver wires to see if he could improve it.

After all, silver is the metal with the best conductivity. Although it is not much stronger than copper, it is worth a try.

Before long, he would be looking for gold in California, aided by a metal detector, even the crudest, far more effective than the naked eye.

Horse Whistle replaced all the conductive parts in the metal detector with silver, and then repeated the experiment.

This detector is so simple and a bit bulky. First of all, it is a square wooden box containing a voltaic pile.

There is an opening in the wooden box, and the silver wire wrapped in cowhide protrudes from it, and is connected to the handle. Below the handle is the indicator fan and coil.

Of course, most of the coils and handles are protected by the wooden case, and a glass is buckled on the indicator fan to prevent it from being affected by the flow of outside air.

For ordinary people, the wooden box containing the battery may need to be carried on the back, but with the shape of a horse whistle, it is enough to carry it in the hand.

In the chief's hall, there are some gold coins on the ground.

Holding the battery box in one hand and the handle in the other, Ma Wiao slowly approached the gold coins from a distance while observing the changes in the fan.

Under his careful adjustment, the fan speed is relatively stable, at least according to the standard of the naked eye.

As the metal detector and the gold coin get closer, the induced magnetic field generated by the gold coin changes the current in it, and the rotation of the fan also changes accordingly, first slowing down, and when the whistle retracts the detector slightly, the fan speed increases again.

When it is far and near to the metal, the fan will jump repeatedly between fast and slow.Under the existing technical conditions, this is the best indicating device that the horse post can think of.

The accuracy is not bad, but the detection distance is still not far, and it can only detect the metal in front of you.

It seems that it can only go so far.

At this moment, when it was raining, he came in from the outside, and immediately saw something in the horse whistle's hand, and asked, "What is this?"

"Metal detector." Ma Whistle said, put the wooden box on the table, and then passed the handle over, "Would you like to try it?"

On a rainy day, he took the handle curiously: "How do I use it?"

"Put this close to the place you want to detect. If there is metal there, the fan speed will tell you." The horse whistle pointed to the detector's coil.

"Really?" Rainy Tian was amazed, and he couldn't wait to pick up the detector and approach the gold coin next to him.

Sure enough, as the horse whistle said, as soon as the detector got close to the gold coin, the fan on it immediately started to slow down.

Around the gold coin, every change in distance brought a change in the fan speed, and once away from the gold coin, the fan stabilized.

"This... this is really unbelievable!" The rainy day couldn't help opening his eyes wide, and then tried it with copper and iron, and found that copper and iron can also be detected by the detector.

"How did you do it?" He turned the detector over and looked at the silver wire coil that was not covered by the wooden case.

"You should be able to imagine that I have taught a little about its principle in the advanced mathematics and science class." Ma Shao said with a smile.

A bit of a headache on a rainy day, obviously he's not very good at math and physics: "Is it Faraday's... law of electromagnetic induction?"

"Almost." Horse Whistle nodded. "Specifically, this detector uses an effect I call 'eddy current'. Of course, other people may not fully understand this effect."

"Including Michael Faraday," he added.

Faraday is still alive, a scientist of great renown.

"Sounds very powerful." Rainy Tian touched his chin, "But this thing doesn't seem to have much practical significance, what are you going to use it to detect, iron ore?"

Horse Whistle: "It can't detect iron ore. In fact, it can't detect almost any mine. After all, it's a metal detector, not a metal ore detector—except for gold mines."

"why?"

Ma Shao continued to explain: "Because gold is not easy to participate in chemical reactions, it often exists in the form of simple substances in nature."

Thinking about it on a rainy day: "So you plan to use it to find gold mines?"

"Hmm...not really." Ma Shao thought for a moment, "After all, gold mines are always rare. In a place as big as North America, when will this small detector find gold mines."

He was actually looking for gold mines.

Although the performance of this detector is not very good, it is definitely stronger than the naked eye.

The detection area is not too large, it is only near Sacramento, so it should be relatively easy to detect the results.

But it is obviously inappropriate to say it directly now, after all, it is so early... He said that there are gold mines near Sacramento, which will inevitably give people a feeling of appointment.

And if you don't designate a relatively small area, it would be too stupid to use this thing to search for gold mines across the continent.

"In that case, what's the use of this thing?" Rain asked again.

"..." Ma Whistle didn't know how to answer for a while, and finally had to quote Faraday's famous saying, "What use can a newborn baby do?"

(End of this chapter)