Harold J. Reilly, owner of a New York gym during the 1930s and 40s, promoted the idea of using children as exercise equipment. Pick them up and swing them around, he urged parents, as one would a dumbbell or kettlebell.
The advantage of using kids as dumbbells, he pointed out, was that as they grow older their weight will increase, thereby naturally helping the parents to develop their strength.
It's an intriguing idea, although a set of dumbbells is
a lot cheaper than having children. And won't break if you drop them.

Minneapolis Star - May 31, 1942

"Reilly recommends that parents (or grandparents) work out by swinging their youngsters around from childhood. Says it helps both out."
NY Daily News - May 2, 1948

Pittsburgh Sun-Telegraph - Aug 3, 1941
Text from the Pittsburgh Sun-Telegraph - Aug 3, 1941:
Some years ago Mr. Reilly was thumbing through a volume of Greek mythology when he read how Hercules, as a boy, started lifting a small calf every day. As the calf grew, so did Hercules' strength so that when it became a full-grown bull Hercules could still lift it.
Mr. Reilly thought that the story could be given a modern twist and proceeded to do so. He became "Hercules" and his infant son and daughter the small "calves."...
For years he carried out this theory conscientiously with his own children and it worked so well that it prompted him to write a recent book about physical culture in which he advocates that both fathers and children will benefit greatly if the former raise the latter as dumb-bells.
"I'm not suggesting that you bring a bull calf into the house and go to work on it. After all you're not Hercules," Mr. Reilly points out in "The Secret of Better Health," published by Carlyle House, "But you can work out the same idea by starting to exercise with your pride and joy when he's only a year old, and keeping it up until he's ten, 15 or even 20. The child will benefit, and so will you...
"You may start when your child is an infant," says Mr. Reilly. "But as babies are delicate, don't begin by wrestling with him. Just manipulate the baby's arms and legs. Wiggle them around, being careful not to twist harshly... Then as the child begins to walk, you can swing him by the arms."...
"From three to six, you can become a little more strenuous. Pick the child up and swing him around, holding him by the arms. Let him lie on his back and take his two hands in one of yours and his ankles in the other and swing him around that way, back and forth, sideways and between your legs as though he were a medicine ball...
Mr. Reilly says that the swinging-around game should be kept up during the six-to-nine period of the child's age. In addition he should be picked up by the ankles and walked around, wheelbarrow fashion...
"From nine to 15 keep up the same exercises, if you can, and begin to box and wrestle with him," says Mr. Reilly. "It is just as easy with a daughter, for a little girl is a natural tomboy. She doesn't begin to be a female until around 12 years when adolescence sets in. Then a certain amount of care is necessary. But until then, treat your daughter the same as your son."
You'll be able to administer all the spankings you desire, if you buy our shirts!
Source.
Starlet Alexis Smith, selected after elimination tests in this "Posture Meter" as the "Perfect Posture Girl" by the College of Osteopathic Physicians and Surgeons of Los Angeles.
The Wikipedia page for Alexis Smith

San Francisco Examiner - Dec 20, 1942

Birmingham News - May 11, 1942
Firestone came out with radioactive spark plugs in 1940. The idea was that radioactive material (polonium) would improve the electrical conductivity of the spark plugs, resulting in better fuel combustion. More details from the
Health Physics Historical Instrumentation Museum:
Other than the slightly improved performance when the plugs were first installed, their benefits were questionable. The short half-life of polonium-210 (138 days) meant that the enhanced performance was only temporary. It also put dealers in the uncomfortable position of having to decide what to do after unsold plugs sat on the shelf for extended periods. Furthermore, the inevitable accumulation of deposits on the surface of the plugs’ electrodes as the vehicle burned fuel would attenuate the alpha particles and prevent them from ionizing the gas.

Monrovia News-Post - Mar 27, 1941
1941: Carl Hutzmann, hair tonic salesman, sued a wig supplier on account of late delivery of a wig. "Hutzmann said that he had to appear before his prospective customers with a receding hair line, so the wig was of no use to him later."

Brooklyn Daily Eagle - Mar 27, 1941
Nov 1946: In a contest of old vs. new technology, the abacus beat a calculator in a contest of speed in all categories (addition, subtraction, and division) except multiplication.
I'm assuming a modern computer should now be able to outperform an abacus, though I suppose it would depend on how quickly one can input the numbers.
More info:
Abacus vs. the Electric Calculator

The Californian - Nov 11, 1946

Detroit Free Press - Nov 4, 1946
1941: Patrick Gunn, 46, left a note in the church collection plate challenging the priest, Monsignor Edmund J. Reilly, to a fight in the street.
I found a photo of the Monsignor. He doesn't look like the fighting type.

Wilmington News Journal - Mar 24, 1941

Monsignor Edmund J. Reilly
source: FindAGrave.com