The tower clock in this building was installed in 1908. It is a replacement for the original; which was destroyed in the 1906 earthquake.
Most of the Bay Areas wind-up tower clocks were made by the Seth Thomas Clock Co. of Thomaston, Ct. and a few others were made by the Howard Clock Co. of Boston.
The movement of your tower clock is extremely rare. Your tower clock has been faithfully wound for the past 98 years. Your clock was made of the finest materials, of the best possible workmanship, and to date, is of the latest mechanical design. It keeps on running, as long as John and Cliff keep on winding.
The clock, here, in the San Jose Museum of Art, is one of about 50 clocks manufactured in the one man clock factory, of a Danish immigrant by the name of Nels Johnson. Both his clock factory, and his machine shop were in Manistee, Michigan. He manufactured sawmill machinery in his machine shop. He kept the clock movement business entirely separate from the machine shop, and never took on an apprentice, not even either of his sons.
Your Johnson clock is of a strong, overbuilt, industrial appearance, and surely was built to last forever. The hour bell inscription, reads something like Nels Johnson, The Century Tower Clock. Itís been running nearly a century now, and has centuries left.
Johnsonís tower clocks sold mostly in the northern mid west regions of this country, and strangely, two ended up in the orient. One could wonder why the U. S. Government bought your Johnson clock, when they could purchase one of the ordinary, and often cheaper brands. This clock never has been given the respect that it deserves, either as a timepiece, or as a time standard. Maybe the advent of radio here in San Jose, only one year later, made the use of such a high quality public clock, unnecessary.
Johnson made a full line of tower clock movements; time only, hour striking, and quarter striking, he employing both dead beat, and Dennisonís double three legged gravity escapement ala ďBig BenĒ.
There was a framed instruction sheet from Johnson on the wall in the clock room upstairs. It gave oiling instructions for the clocks movement, it was dated 1908. He said to oil the clock movement every time you wind it. He failed to say just where to oil, so the entire clock movement has been covered with oil.
Johnson began manufacturing clock movements in about 1886. The present clock is much larger in scale than is necessary to run this towers three 7í dials. If the movement was new in 1908, he must have understood the order to be for a clock that was capable of running 17í dials, instead of 7í dials. The movement is huge in scale, compared to the common Seth Thomas or Howard clock movement. The Seth Thomas or Howard clock would have had a time driving weight of about 150 lbs., the Johnson clock has a time driving weight of 500 lbs. The gears of the common Seth Thomas movement were comparatively narrow in width, and the Howard gears were a little wider than the Seth Thomas gears. Both brands gears were small in scale, when compared with the gears of your Johnson clock. The Johnson has gears of gun metal, and fine grained cast iron. The pinion gears and pivots are of hardened steel. The Johnson clock has much higher gear tooth count ratios than a Seth Thomas or Howard clock did; which means that the Johnson clock has much less rubbing friction between the gear teeth than the common brands did. The Johnson clock was a much more difficult movement to make, and is made of superior materials than the ordinary clocks. The Johnson clock, which has received virtually no care for most of the past 98 years, shows very little wear. However it has been covered with solidified oil and abrasive concrete dust for years.
The Nels Johnson clock upstairs has a temperature compensated pendulum. The 14í rod, which suspends the cast iron pendulum bob, is composed of concentric zinc and iron tubes; which raise and lower the pendulum bob automatically. Such a pendulum helps prevent changes in the running speed of the clock due to changes in the ambient air temperature. In other words, a pendulum like you have upstairs prevents the clock from slowing down when the weather is hot and running faster when the weather is cold.
I donít know why such a fine clock was installed in this building. Somebody may have had really big plans for your clock; which never came to pass. Perhaps it was because of your proximity to Lick Observatory. There, you could obtain the real time. Someone could telephone the observatory, and obtain a time reference to accurately set a clock. Such a sophisticated clock as your Johnson was capable of keeping accurate time for long periods of time, but a correct time reference was necessary.
The Johnson clock was capable of keeping very accurate time, and could have been used as the time standard for San Jose. Since we had radio one year later, the Johnson was probably never used to its full potential.
Your Johnson clock originally had electrical contacts which closed once per minute. They may have been intended to impulse slave clock dials, or be the source of some sort of city time signal. There is no evidence that they ever have been used.
The only other tower clock in the San Francisco Bay Area, of comparable time keeping ability to the clock here, is in the San Francisco Ferry Building. In the case of the Ferry Building, the electrical contacts were used to operate 23 slave clocks and sound a siren several times a day. It was the time standard for San Francisco.
Both the San Jose Museums Johnson clock, and the San Francisco Ferry Buildings Howard clock employ Dennisonís double three legged gravity escapement. The prototype for this escapement is in the clock at the Houses of Parliament in London. The hour bell of the Parliament clock, is known as ďBig BenĒ.
The escapement of a clock is the part that keeps the pendulum swinging. The hands are indicators of how many times the pendulum has swung. For a tower clock to keep reliable time, it must have a reliable escapement. The clock pendulum impulse must be independent of the influences of wind or pigeons sitting on the hands. All three of the clocks that I have mentioned, have the same type of escapement, and to date, is the latest. All three have 14í pendulums which tick every two seconds. These clocks keep their pendulums swinging by releasing a small weighted lever against the pendulum rod every two seconds.
The Johnson clock movement in this building was pictured on the inside back cover of the San Jose telephone book in about 1980. The time telling part of the movement had just been cleaned, and was still bright and shiny.
The hour striking part of the clock movement has never been cleaned. The time telling part of the movement was cleaned in 1979. The hours can be struck on the Museums 1,700 lb. Meneely bell, and were until the early 1970ís.
A new ultrasonic burglar alarm was installed in this building in the early 1970ís. The hourly striking of the clock bell tended to trigger the burglar alarm at night; so the strike was allowed to run down and the bell has been silent since.
Speaking of the early 1970ís, the person who had the privilege of winding the clock wound it every two days. It was too tiring to wind it once a week. They didnít like the sound that the ratchet made when winding the 600 lb. strike weight. So, they held back the strikewinding ratchet to silence it. Unfortunately, they had failed to insert the pin that keeps the winding crank from coming off. The 600 lb. strike weight dropped through two floors and lodged in a wall, one floor above the directorís desk. The Museums director, Albert Dixon, was sitting at his desk, and thought that the Museum had been bombed. The building damage was quickly repaired, and a local machine shop repaired the damage to the movement. A wise person placed a plywood covered pile of old car tires in the tower beneath the clock weights. It was intended to absorb the impact if either of the weights should ever fall again. The next generation installed air conditioning in the building. They missed the concept of the pile of tires, and moved them to install an air conditioning duct, where the pile was. And that is the way it is today.
Part of the clock movement is bright nickel-plated. The plating looked very nice, but was a needless expense, because only the clock winder would see it. It is possible that this clock was a display piece of Johnsonís work, and happened to be available when this building was being rebuilt after the 1906 earthquake.
Under the dirty layer of darkened oil, which covers the clocks iron frame, is a colorful green paint job, with red pin striping. It may be possible to remove the darkened oil, and preserve the original paint. Itís worth a try.
The Johnson clock is a fine example of one of the rarest American tower clocks in existence. Maybe someone will allow you to climb the tower and take a look at it.
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