He came to the U.S as a teacher of the deaf, and conceived the idea of “electronic speech” while visiting his hearing-impaired mother in Canada. This led him to invent the microphone and later the “electrical speech machine” — his name for the first telephone.

75 years (1847–1922)

Deceased (1847–1922)

Mabel Gardiner Hubbard

He invented a rudimentary metal detector in a quest to save the life of a president. Alexander Graham Bell and assistant use an electrical detector to find a bullet inside President James Garfield. After Garfield’s death on September 19, the bullet was found to be on his left side.

Metal detectors: In 1881, Bell invented the first metal detector in an attempt to save President James Garfield who laid dying of an assassin’s bullet.

One of the most difficult metal to locate with a metal detector is stainless steel because steel has poor electrical conductivity and also has low magnetic permeability….Other items that cannot be detected with a metal detector include:

• Pearls.
• Diamonds.
• Paper.
• Stone figurines.
• Bones.
• Liquid.
• Glass.
• Plastic.

In the 1960s, the first industrial metal detectors were produced, and they were widely used for mineral prospecting and other industrial purposes.

The short answer is “no”, however, for some prospectors, having a metal detector in their repertoire has proven quite useful. The use of a metal detector for prospecting differs from the panning method however.

The Best Metal Detectors for Your Money

• Editor’s Pick. Garrett. AT Pro Metal Detector.
• Best for Low Prices. Garrett. ACE 400 Metal Detector.
• Best All-Terrain Detector. Minelab. CTX3030 Metal Detector.
• Best for Underwater. Minelab. Excalibur II Metal Detector.
• Best for Finding Gold. Nokta. Gold Kruzer 61KHZ Waterproof Metal Detector.

For instance, all metal detectors will find gold but there are different types made that are more sensitive to and specifically for gold. So, if you are solely interested in locating gold jewelry, you will want to select a detector made specifically for this purpose. Some metal detectors are water proof.

Gold in stomach and anus In the past, gold was made into blocks for smuggling, but now it is smuggled in emulsified or molten form. It is difficult to detect gold when it is brought in an emulsified form. Neither scanning or metal detector can catch it.

Can a Metal Detector be Useful for Finding Diamonds & Gemstones? This leads to an important point: metal detectors will not detect non metal items such as gemstones, diamonds and pearls.

Most metal detectors can detect objects about 4-8ʺ (10 – 20 cm) deep. In ideal conditions, a mid-range metal detector can reach 12-18ʺ (30-45 cm) underground. Some specialized detectors can go as deep as 65′ (20 m).

Deepest Metal Detector Reviews

• Makro DeepHunter 3D Pro. This is not your everyday kind of buy.
• Minelab GPX 5000. The GPX has pulse induction technology.
• Garrett ATX Extreme. Pulse induction rules when it comes to depth, and fortunately, the ATX isn’t as expensive as other PI detectors.
• Minelab Equinox 600.
• Garrett ACE Apex.

Modern prospecting detectors can discover gold as small as a half a grain. As the size of the target becomes larger, gold nuggets can be located at significantly greater depths. A single grain nugget can be unearthed at a depth of 1-2 inches.

South Africa has the world’s deepest hard rock gold mine up to 3,900 metres (12,800 ft) underground. At such depths, the heat is unbearable for humans, and air conditioning is required for the safety of the workers.

Approximately 192,900 tonnes of gold exists on the surface. One Olympic swimming pool of gold therefor would contain 48,300 tonnes of gold, just over 25% of all the gold. So no, it would actually fill nearly four Olympic sized swimming pools, only 300 kg shy.

Based on known reserves, estimates suggest that gold mining could reach the point of being economically unsustainable by 2050, though new vein discoveries will likely push that date back somewhat. Fortunately, gold hasn’t run out yet and is widely considered a wise investment option for any investor.

Average human body has 0.2 milligrams of Gold. One of the lesser know elements is actually Gold. An average person’s body weighing 70 kilograms would contain a total mass of 0.2 milligrams of gold.

03/4​Is edible gold safe? Gold has been used since ancient times in medicines, dentistry and as a food decor ingredient. Scientifically, gold is inert and doesn’t break down easily. In fact according to experts, pure edible gold doesn’t break down and dissolve in the bloodstream.

So, with regard to any vessel used for eating and drinking, it is not permissible for it to be made of gold or silver, or to be plated with those metals. “The scholars are unanimously agreed that it is not permissible for a Muslim to eat or drink from vessels of gold and silver.”