The U.S. gun companies at that time (except Colt) had a little problem. Or rather a tall, thin Mormon problem, known as John Moses Browning. The said Mr. Browning had invented, and patented, just about everything having to do with autoloading pistols. He didn't use all his ideas, but he kept others from using them.
When S&W decided to try its hand in the hot auto pistol market, the unpleasantness known as WWI had not yet begun, so off went Joe Wesson, the chief designer, to Europe, where he discovered the Clement automatic, a small pistol made in 5mm Clement and in .25 ACP. That pistol didn't have a slide combined with a breechblock (a JMB patent) and didn't appear to violate any of the other Browning patents.
So S&W chose to do a one-up on Colt's .32 ACP and came up with its own .35 S&W. Not only was the bullet bigger, but the first ones were made with a unique system in which the bullet held a quantity of grease. The pressure of firing drove in a plug that squeezed the grease out through holes in the bullet as it went down the barrel. If that "refinement" was not enough, S&W was also concerned about barrel wear but wanted a jacketed bullet in order to feed properly. So the .35 S&W had a jacketed nose, but the sides of the bullet were exposed lead!
Then came the inevitable "Ooops" factor. The Clement was made for low pressure rounds. The .35 S&W was considerably hotter, and the small breechblock was not heavy enough to keep the lid on until the pressure dropped. Building in a locking system was simply not feasible, so they provided a very heavy spring. But that meant no one less muscular than King Kong could retract that breechblock. The "solution" was to provide a means of disconnecting the spring from the breechblock, and that was done.
But JMB had patented the simplest safety, and S&W came up with a wheel type built into the backstrap. A grip safety? Sure, but it had to be different from Colt's, so S&W put it in the front (where it pinches the hand!). Not unsurpisingly, the public reacted to the new gun with wild, unrestained - well, yawns. It was a disaster. The company redesigned the gun, yielding to demand and chambering it for .32 ACP. The new offering was met with even less, if possible, enthusiasm, and was another financial disaster.
S&W gave up on autoloading pistols and it was not until the 1950's that they developed one for a planned military test and adoption that did not come off.
S&W never really gave up on the Clement look, though. Their Models 41, 46, 61 and 22 all have some resemblance to the early .35 auto.
Jim
but I do love those odd guns & cartridges though...