know. Last straw and all that sort of thing? Uh-huh!

"Did you ever see my set of rules for resigning? I framed them up years ago when I was in the newspaper business, and I have used them ever since. I have resigned often since then, always in the way prescribed in these rules. Perhaps they will be of service to you. Here they are:

"Rule 1. After receiving the last straw, don't do anything for two hours. Above all, don't write anything.

"Rule 2. At the expiration of two hours, write your resignation, and make it as hot as you can. Relieve your feelings, and say everything you have been penning up in your breast. Scorch the scoundrel.

"Rule 3. Then go home.

"Rule 4. The next morning immediately upon arising, read over your resignation, and tear it up.

"Rule 5. Go to work at the usual hour.

"Take a copy of them," concluded Mr. Wynne, "and you will find that they are absolutely essential to any man who expects to resign frequently and still continue to rise in the world."-New York Times.

other day I discovered that the bathtub needed a new coat of varnish. I told him, and he said he'd attend to it that night if I'd get the varnish. So he came home early and I told him the varnish was in the cupboard with the groceries. He took off his coat and applied the varnish, while I got dinner.

"Goodness," he said, as he tasted the soup, "this tastes just like a paint shop. That varnish odor gets into everything."

It tasted queer to me, too; but I felt my reputation was at stake and wouldn't admit it. After dinner we went to look at the bathtub. It was very queer-looking, and had curious lumps all over it.

"Where did you put the empty varnish can, George?" I asked him. I had certain suspicions.

"Out in the back yard," he answered.

I went out and found it later. The poor boy had actually varnished the bathtub with the ox-tail soup we should have had for dinner, and-yes, I suppose there's no doubt we ate the can of varnish. But I wouldn't let him know it for the world. He'd feel so chagrined. -BESSIE B. RIDE.

How to Resign

"GOING to resign, are you?" asked Assistant Postmaster-General Wynne of an indignant person who had been pouring his grief into his ears. "Can't stand it another minute, eh? Put up with it as long as you could, and now you're going to throw up your job and tell your chief what you think of him? Yes, I

Perpetual Motion at Last

TO THE EDITOR: I submit herewith the drawing of a working model of a perpetual motion machine. I know how other inventors who have worked along this line have been made fun of, and the fear of ridicule has for years kept me from making my invention public. In fact I invented it while still a small boy, and I think a single glance at the drawing will show how simple both the machine and its inventor are.

The machine consists of a number of radial arms, to the end of each of which is attached

a weight, the whole revolving on an axis. The machine revolves from right to left. As it turns, the weights attached to the ends of the arms gradually change from 6 to 9 pounds each, the transformation being reversed as the weights begin to rise. This may seem complicated-even absurd-to some; but every great invention has been laughed to scorn by the ignorant and fatuous populace. Besides, a single glance at my drawing will show that in spite of what physicists may say, the weights on my machine do act in just that way.

I am not looking for any financial reward. I shall be satisfied if no one throws a brick.I. N. VENTOR.

O

NE of the immense industries of California is the manufacture of salt. A vast amount of capital is now invested in this constantly growing business in the Golden. State. Great quantities of salt are used, not only in California, but all along the Pacific Coast-especially in the northwest, where there are located many large fishing establishments, packing houses,

etc.

The time is not so remote when California imported all of its salt supplies. It may now be stated, however, that nearly all the home consumption is produced in the State; and not only so, but very large quantities also are now annually shipped to the Pacific Coast States. and beyond the seas.

All the salt produced in California is obtained by evaporation from ocean water, there being but few salt springs or wells. With the exception of the output of a few comparatively small saltmanufacturing plants in the southern part of the State, the entire salt production of California is made in Alameda county, within an area

of less than thirty square miles. Probably not less than 25 large salt plants are at present in operation around the lower arm of San Francisco Bay. Over on the northern side of this arm, in San Mateo county, are a number of smaller establishments.

It is estimated that the total output of salt per year in Alameda county alone reaches 100,000 tons; while not less than 50,000 tons are annually produced in other parts of the State.

The salt produced from sea water has no superior in the world, in strength and purity. There is every grade produced, down to the very finest table salt, by certain refining processes. The salt output of California is shipped to the northern States of the Pacific Coast, British Columbia, Mexico, Central and South America, Hawaii, Japan, Russia, and even the Philippine Islands.

Among the largest salt-producing plants located in Alameda and San Mateo counties are those of the following companies:-American Salt, Union Pacific Salt, Carmin Island, Crystal Salt, Pioneer, Alameda, Russell, Mount Eden,

Continental, Leslie Salt, and Westshore & Redwood City. Besides these are many others operated on a smaller scale.

No region in the world manufactures this indispensable article of commerce in greater quantities than California. Millions of dollars of capital are involved in the manufacture, and a small army of men is constantly employed.

The summer season is the best period for making salt. It is collected in the warm part of the season after evaporation has done its work, and piled up in

alyzes higher than the Liverpool importation, and is superior for table and dairy purposes. Large quantities of this salt are used in the curing of all kinds of meat and fish-salmon, codfish, etc.

All along the lower arm of San Francisco Bay there exist certain peculiarities in the lay of the land, which, in conjunction with the climate and the favorable conditions of the soil, combine to make the locality especially adapted to the salt industry. Long intervals of cloudless skies, low humidity, and high

great pyramids, some of which contain as much as 4,000 tons. It is very beautiful-snow-white and dazzling in the sunlight There are hundreds and even thousands of acres covered with these pyramids, and the scene is a strange one.

In the process of evaporation, the sea water is run into a series of ponds, and tested with the salometer and other instruments a number of times each day. All impurities are in this manner allowed to settle, and are extracted in the countless different ponds built for such purposes, until finally all that remains is the salt pickle, or strong brine, which is pumped into the vats. The result is that the salt comes out perfectly clean, sweet, and pure. No artificial means are employed to produce the snowy whiteness.

It is claimed that California salt an

temperature all favor rapid evaporation; while the soil-a stiff clay-is well adapted for making levees and watertight reservoirs.

The great natural deposits of rock salt found in various localities in the vast region west of the Rocky Mountains, are commercially of comparatively small value, owing to their remoteness from distributing markets and to the necessarily high cost of transportation. Except for a small local demand from farmers, ranchers, and meat dealers, the yield of these deposits is comparatively insignificant, and figures but little in general statistical records. The cost of evaporated salt is but one-fifth of the lowest rate of transportation on rock salt from the nearest source of supply to the most accessible ocean port.

Invitation to Readers

THE

'HE TECHNICAL WORLD MAGAZINE is published for the information, as well as for the entertainment, of its readers. Primarily its purpose is to be helpful, rather than merely interesting.

Are you puzzled by any question in engineering or the mechanic arts? State your problem in writing, and mail it to the Consulting Department of THE TECHNICAL WORLD MAGAZINE. It will be answered as speedily as possible by an expert especially familiar with the questions involved. For the purpose of having the work done thoroughly and in an authoritative way, THE TECHNICAL WORLD MAGAZINE has made arrangements with the American School of Correspondence to have all problems of a technical nature submitted by its readers answered by the members of the school's staff of professors.

If the question asked or the problem presented is of general interest, the solution will be printed in the columns of the magazine. If of merely personal interest, it will be forwarded by mail, provided an addressed and stamped envelope is enclosed for the purpose, when the question is sent in.

Hammering Circular Saws QUESTION: What is the method of hammering circular saws?-W. P.

Answer: The saws should be examined by those who take charge of them,

to see what the tension is when first received. The tools required are two straight edges, one from 14 to 18 inches long, one about 48 inches long; one trymandrel; one round-face and one crossface hammer; and an anvil.

By placing the straight edge on the saw when laid on the anvil, it can easily be seen if tension is lost. The saw should be tested all around to see if any part between the edge and the center falls away. Such spots should be marked, and should not be hammered as much as other parts, if at all. In testing for the tension, be sure to have the straight edge crossing the saw diametrically from that point of the saw that rests on the board, the opposite edge being raised by the left hand, while the straight held edge is and gently pressed down with the right hand. Do not lean the straight edge to one side, but hold it up straight, or it will fall to the form of the saw and not show what is desired. A straight edge reaching from the center hole well out to the edge of the saw, is the best to use in hammering to regulate the tension; and when this straight edge is applied as above, the saw should fall away from a straight line; this will show that the center of the saw is stiff.

It is very seldom necessary to hammer a saw at the part covered by the collar. When commencing to hammer, see that the face of the hammer is ground so that the blow will be round; and do not strike too heavy, for it is better to go over the

saw a number of times than to hammer too much at one operation and thus put the saw in worse shape than it was before hammering.

The hammering should occur at the points indicated by the dots in the figure. After going around on one side, mark off the other side, and repeat the operation with as nearly as possible the same number and weight of blows as struck on the first side and as directly over them as possible. Now, stand the saw on the floor; hold it up straight, and test it with the long straight edge. If the hammering has been done alike on both sides, the saw will be very nearly true. If, however, it shows full on one side and dishing on the other, mark the places that are full.

Place the saw on the anvil with the round side up; hammer lightly on full places; test again with the long straight edge; and if it appears true, put it on the anvil to see if it has the proper tension; if not, repeat the operation with the round-face hammer. When it has been regulated to the proper tension, the most difficult part of the hammering will have been accomplished.

Next put the saw on the try-mandrel, and test it with the short straight-edge for running true. Mark the places as they run on or off, while turning the saw slowly around. Where the saw runs off, the lumps must be taken out with a crossface hammer, and struck in the direction that the straight edge shows the lumps to run. The saw may also be thrown out of true by lumps running toward the center. In this case, the saw will be on or off at points about opposite each other. This part of the hammering must be done carefully; and if the hammering is of the proper weight and the face properly ground, the saw can be made to run true without altering the tension to any ex

tent.

The testing on the mandrel should be with the full side of the saw towards the pointer; and by knocking down the lumps from that side, the plate will be made flat. When the saw is fairly flat, test it from both sides. Next put the saw on the arbor; and if to be run at a high speed it will sway gently from side to side in getting up to full speed, and may

then run steadily and do its work. If it does not, but rattles in the guides, it needs to be made more open toward the center. An experienced man can stand the saw on the floor, and, by giving it a sudden shake at the top edge, will know it is open toward the center if the center vibrates and the edge stands stiff. If the saw should be buckled by an accident, true it with the cross-face hammer before regulating the tension and final truing. Do the same in case of buckling caused by burned spots or sharp lumps over the collar line. These may be knocked down by placing two thicknesses of strong, heavy paper on the anvil, when, by a few well-directed light blows, the lumps can

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DIAGRAM ILLUSTRATING METHOD OF HAMMERING
CIRCULAR SAWS.

be hammered without expanding the metal to the same extent as if straightened on the bare face of the anvil. It is very important to have the blows distributed properly over the surface to be hammered. Hammering too much at one place causes a loose spot or lump that will be difficult to take out. In hammer

ing with the round-face hammer, work on lines drawn from the edge toward the center. This will prevent putting twist lumps in the saw and obviate much of the trouble in truing with the cross-face hammer.

If it is necessary to go over the hammering more than once for tension, do so on lines between those that have al

ready been operated on. The round

face hammer should have its face so