Hydraulic Mining

Hydraulic mining was a form of mining that used water to dislodge rock material or move sediment. Typically, intense jets of water were pressurized in an ever-narrowing downward channel or hose and aimed at a hillside or riverbank, shearing off huge amounts of land and breaking it apart, washing the resulting debris into a huge sluice that extracts the gold from it.

Hydraulic mining represents the middle of three main phases of the Gold Rush. In the first phase, which lasted only about 10 years, individual gold miners mined for gold by hand with pans, sluice boxes, rocker boxes, and long toms. In the second phase, which lasted about 25 years, corporations with heavy equipment used jets of pressurized water to mine much larger amounts of dirt and gravel at a time. (Hillsides sliced in half by hydraulic mining can still be seen at Malakoff Diggins State Historic Park.) In the third phase, which lasted more than 50 years, corporations used huge dredging machines to dredge up the same dirt and gravel that had already been mined hydraulically and re-examine it to extract any gold that had been left behind during the hydraulic mining phase.

Of the three phases, hydraulic mining was the most devastating to the environment. The debris from cliffsides and riverbanks broken apart by hydraulic mining washed into the rivers and was carried downstream. When the rivers reached the Sacramento Valley, the flatter land allowed the river currents to slow down, which caused the water to stop carrying the debris along with it. The debris settled to the riverbottoms, raising them until the rivers spilled out of their channels and flooded the valley farmlands. Huge amounts of this debris were dumped into all four of the rivers that pass through Yuba and Sutter Counties. Farmers such as George Ohleyer and James Keyes formed the Anti-Debris Association, which sued the hydraulic mining corporations. In 1884, Judge Lorenzo Sawyer of the U.S. Court of Appeals Ninth Circuit in San Francisco decided in favor of the farmers, prohibiting hydraulic mining in the watershed areas of navigable streams and rivers. In 1893, the U.S. Congress passed the Caminetti Act, which modified the judge's ruling somewhat by allowing hydraulic mining in those areas only if a debris-retaining dam was built to prevent the debris from flowing downstream. Some small-scale hydraulic mining then resumed, accompanied by brush dams and log crib dams to retain the debris. However, most of the water-delivery infrastructure had been destroyed by an 1891 flood, so this later period of hydraulic mining never approached the scale of the more environmentally devastating hydraulic mining that had preceeded the judge's ruling.

W. T. Ellis, Jr., for whom Ellis Lake was named, wrote in his autobiography Memories: My Seventy-Two Years in the Romantic County of Yuba, California about the vast scale of the destruction caused by debris from hydraulic mining:

QUESTION: Just what is hydraulic mining?

ANSWER: In the famous decision of Judge Lorenzo Sawyer of the United States Circuit Court, in 1884, he states, "Hydraulic mining, as used in this opinion, is the process by which a bank of gold-bearing earth and rock is excavated by a jet of water, discharged through the converging nozzle of a pipe, under great pressure, the earth and debris being carried away by the same water, through sluices, and discharged on lower levels into the natural streams and water courses below. Where the gravel or other material of the bank is cemented, or where the bank is composed of masses of pipe-clay, it is shattered by blasting with powder sometimes from fifteen to twenty tons of powder being used at one blast to break up a bank. In the early periods of hydraulic mining as in 1855, the water was discharged through a rubber or canvas hose, with nozzles of not more than an inch in diameter; but later, upon the invention of the 'Little Giant' and the 'Monitor' machines, the size of the nozzle and the pressure were largely increased, till now the nozzle is from four to nine inches in diameter, discharging from 500 to 1,000 inches of water under a pressure of from three to four or five hundred feet. For example, an eight-inch nozzle at the North Bloomfield mine discharges 185,000 cubic feet of water in an hour, with a velocity of 150 feet per second. The excavating power of such a body of water, discharged with such velocity, is enormous; and, unless the gravel is very heavy or firmly cemented, it is much in excess of its transporting power." (18 Fed. 753.)

QUESTION: What quantity of material was moved in this way?

ANSWER: In 1904, at the request of the Hydraulic Mining interests, President Roosevelt sent out Professor G.K. Gilbert, of the U.S. Geological Survey Department to investigate and ascertain if there was some other way of solving the miner's difficulty other than by the Caminetti Act. Professor Gilbert spent three years on his investigations and made a very complete report but his conclusion was, there was no other way to handle the problem. This report disclosed the fact that the amount of deposits of mining debris between the years 1849 and 1914 in the San Francisco Bay system amounted to 1,146,000,000 cubic yards; that on the water sheds of the Yuba, Bear and American Rivers alone, there had been excavated 857,670,000 cubic yards of mining material which was eight times more material than was excavated in the construction of the Panama Canal.

QUESTION: How much material is left in the lower rivers?

ANSWER: According to Major William W. Harts of the California Debris Commission, "The low water plane of the Yuba River at Marysville was raised 15 feet between the years 1849 and 1881. Between the years 1881 and 1905 there was an additional raise of three feet, making a total raise in the low water plane of 18 feet (the actual fill in the main channel being 26 feet). The depth of fill of mining debris in the Yuba River averaged from 7 1/2 feet at Marysville to 26 feet at Daguerre Point and 84 feet at Smartsville. A short distance east from Marysville, the bed of the Yuba River was 13 feet above the level of the surrounding farms." The quantity of material lodged in the river due to mining has been variously estimated, but it seems safe to say that there are now (1905) upwards of 333,000,000 cubic yards in the bed of the lower Yuba, this in a distance of about eight miles above Marysville." Remember, this was only on the Yuba River; other rivers such as the Feather, Bear, American, etc., were similarly affected with mining debris deposits.

QUESTION: Is there any of this material at the present time still left in the mountain canyons?

ANSWER: According to Colonel T.H. Jackson of the California Debris Commission, there are "Nearly 620,000,000 cubic yards remaining lodged in the river beds and mine dumps in the mountains and in the large deposits built up at the point where the mountain streams enter the valley." This material is gradually being washed down to the navigable rivers and bays.

QUESTION: At this time about how much mining material is there in the lower rivers?

ANSWER: According to Colonel T.H. Jackson, "Nearly 96,000,000 cubic yards remain in the navigable channels of the Sacramento and Feather Rivers."

QUESTION: What effect has this material dumped in the rivers had on navigation?

ANSWER: Before the advent of Hydraulic Mining, tidal effect was felt up the Feather River to Nicolaus, 19 miles below Marysville, or about 175 miles from San Francisco by river. The Feather River was navigable to Oroville, about 141 miles from the mouth of the Sacramento River and the Sacramento River itself was navigable to Red Bluff, about 250 miles from the mouth of that river. Mining debris, however, ruined navigation on the Feather River many years ago and it is not being navigated now. The Sacramento River to Colusa is now very difficult at times to navigate.

QUESTION: Notwithstanding the fact that you state that navigation in the Feather River has been destroyed by hydraulic mining, and I understand also that the Sacramento River has but little navigation above Colusa, is the main channel still valuable for navigation?

ANSWER: The Sacramento River has not only been a prime factor in the tremendous crop production in the Valley, but it is equally valuable as a channel for the transportation of products. It is said of the Sacramento River that it leads all streams in the world in its shipment of products grown along its banks. In the last eight years, the tonnage handled averaged 1,272,534 tons per year, to the value of $69,576,499 per year and at the same time an average of 85,760 passengers were transported annually. Please understand that to maintain this navigation is expensive to the Federal Government and on the navigable portion of the Sacramento River last year, it cost a total of $186,441.78 to dredge out mining debris bars and various other kind of work to permit this navigation, and this kind of expense has been going on annually for a long time and will be necessary for a long time in the future. From this it may be seen that the Sacramento River is too valuable a river to permit being damaged to any further extent by the rehabilitation of hydraulic mining behind dams which may or may not restrain such debris, and 96,000,000 cubic yards of mining debris now in the navigable river, is more than sufficient to cope with without being added to in even a minor degree.

QUESTION: Assuming the possibilities of a dam failing, is the element of danger greater if the dam is filled with debris or filled with water?

ANSWER: There is always an element of danger to any dam. Engineers will claim that they can be built so they will not fail, but what guarantee can be given? We KNOW that in recent years, very finely constructed dams HAVE failed, not only here in California, but in other parts of the United States and as we in the Valley see it, there would be vastly more danger if a dam failed which was used more largely for the storage of debris than for water. For example, assuming that a dam was built at the "NARROWS" near Smartsville, about 20 miles upstream on the Yuba from Marysville, and should be restraining water alone; if the dam should fail, a huge quantity of water would be released which would overflow a large area, but in a brief time the water would have drained off and the discharge might result in an improvement in the channels of the river itself. On the other hand, if that same dam should fail filled largely with mining debris, that enormous amount of mining debris dumped into the river would undoubtedly have the effect of filling it up for quite a number of miles and cause the river to adopt an entirely new channel and results would be not only disastrous, but almost impossible to correct afterwards.

QUESTION: What effect has the filling of the rivers had on the valley farming lands?

ANSWER: The filling of the river channel resulted in an almost annual overflow of the farming lands, necessitating the construction of levees by the land owners at enormous expense.

QUESTION: Did the stoppage of hydraulic mining cause material loss to the miners?

ANSWER: The mining interests have stated on many occasions that the Sawyer Decision resulted in the confiscation of $100,000,000 worth of property in the mining districts, but in view of the fact that hydraulic mining was commencing to prove unprofitable about the time of that decision, it is rather difficult to believe that there was that much loss entailed to the hydraulic mining interests and no facts have ever been given to substantiate that figure.

QUESTION: What has been the cost of levees, etc., made necessary by hydraulic mining?

ANSWER: In the report of Major U.S. Grant, 3rd, Document No. 3, Sixty-ninth Congress, he states that the "expenditures by local interests both for flood control and reclamation since 1850 and up to 1925 amounted to $86,645,855.87, and in addition the State of California had advanced the sum of $4,479,463.76, making a total of $91,125,319.63." As this does not include expenditures by the United States Government itself and as it does not include irreparable damage done to large areas of farming lands, it is readily to be seen that the total damage and expense made necessary in the Valley because of the operations of hydraulic mining amounted to vastly more than the $100,000,000 "confiscation" claimed by the hydraulic mining interests.

QUESTION: Was there only one suit to stop hydraulic mining?

ANSWER: No, there were scores of suits with different mines.

QUESTION: Who stood the expense of these suits?

ANSWER: The early suits were largely financed by voluntary subscription by the landowners whose lands were affected, and up to the year 1882 there had been contributed in this way by private subscriptions a little over $65,000 for such purposes. About that time Yuba and Sutter counties through their Boards of Supervisors jointly financed these suits and between the years 1882 and 1907 inclusive, the two counties had jointly expended $394,983.62 in this way; then Sacramento County joined in and took charge of the litigation. Please understand that this is for legal expense alone. In addition to this, Yuba and Sutter counties in the meantime, up to 1901, had expended $5,747,329.59 for construction of levees. Since that time many million dollars additional have been expended under the State Flood Plan by these two counties.

QUESTION: Do you mean to say that the burden of the expense for litigation to stop hydraulic mining was all upon a few counties and that while those counties were endeavoring to save themselves from destruction from hydraulic mining, they were at the same time practically making the fight to prevent the destruction of the navigable rivers and bays, and that the federal government itself had not, and did not, make any effort itself to protect its rivers and bays?

ANSWER: Yes, I mean just that. Also, that after the U.S. Circuit Court finally went on record in the Sawyer Decision, even then, those same counties had to furnish the funds to carry out the Court's decrees.

QUESTION: Were there other expenses necessary besides legal expenses?

ANSWER: Yes, in every suit before it was commenced, it was necessary to get proper information that mines were operating and doing damage so as to have proper testimony to prosecute such suits. This information was very difficult to obtain because the mine owners had armed guards surrounding their mines to ward off any outsiders who might come near the mines.

QUESTION: What was the real deciding suit in this legal fight?

ANSWER: This was the decision of Judge Lorenzo Sawyer, of the United States Circuit Court in 1884. The decision was very lengthy, the testimony was contained in 12,000 pages of printed matter.

QUESTION: Did this decision state that hydraulic mining was illegal?

ANSWER: No; but it did declare that the dumping of the by-products (debris) from hydraulic mining into the rivers was illegal.

QUESTION: Is the principle laid down by this Sawyer decision the law of the land today?

ANSWER: It is.

QUESTION: Did hydraulic mining immediately cease after this decision?

ANSWER: No, for the reasons just set forth, that it was difficult to obtain information to sustain suits against mines because of armed guards surrounding the mines.

QUESTION: Was it not arranged later on to license hydraulic mining?

ANSWER: Yes, in 1893 the Caminetti Act was adopted by Congress at the request of the mining interests and it is still in force at the present time. Under this act a hydraulic mine was permitted to operate after it had obtained permission to do so from the California Debris Commission which consisted of three United States Government Engineers. Before such permission was granted, the mine owner had to convince this Commission that it would be possible to properly restrain the mining debris by dams, etc.

QUESTION: Did this act provide for government cooperation in building dams for storage of debris?

ANSWER: Yes, but this cooperation required a payment of three per cent of the gross proceeds of mining for storage and no dam was ever constructed under this provision, or ever asked for by the miners.

QUESTION: About how many licenses have been granted under the Caminetti Act between 1893 and the present time?

ANSWER: Something like 1000 licenses have been granted and I might state that the Valley interests have never made a single objection to any permit so granted, as we had perfect confidence in the fairness and good judgment of the members of the California Debris Commission, the personnel of which changes about every 4 years. At the present time, 29 mines are operating under permits.

QUESTION: Did the Caminetti Act prove satisfactory to the miners and accomplish what they had expected of it?

ANSWER: No, the restrictions which were imposed upon the miners irked them and they became dissatisfied and finally in 1905 President Roosevelt, at the request of the California Miners' Association, sent out Professor G.K. Gilbert of the U.S. Geological Survey to investigate conditions both in the mountains and in the valleys and endeavor to ascertain if there was any possible way to rehabilitate hydraulic mining. Professor Gilbert put in three years on this work and made a very voluminous report contained in a book of some 150 pages and under the head of "THE OUTLOOK FOR HYDRAULIC MINING," appears the following significant statement: "The regulations that restrain hydraulic mining should not be made less stringent unless the advantage from the mining is of greater moment than the disadvantage to navigation that the change of policy might entail." His conclusion was that there did not appear to be any way to solve this problem other than under the Caminetti Act. Might I not relate a rather amusing experience that befell Professor Gilbert? When he first came to make his investigations, he spent considerable time in the Bay area, then he came to the Valley and I had the pleasure of showing him about here for several weeks the result of mining and our levee building; he then announced one day that he was about to investigate the mining section and I suggested that he keep away from the mines but go direct to the owners and have them show him around. As he related the matter to me later on, when he left for the mountains, on his way up he saw a hydraulic mine at some distance from the road and his curiosity getting the better of him, he tied his horse at one side of the road and proceeded on foot to get a better view of the mine. When he got quite close, he was suddenly confronted by a man armed with a shotgun who demanded that Mr. Gilbert depart. Mr. Gilbert endeavored to explain but without avail and departed and then went to the mine official's office. Later, when the officials were apprised of the occurrence, they were profuse with apologies to Mr. Gilbert but the occurrence apparently made quite an impression on him besides the evident amusement he got out of it.

QUESTION: What happened next?

ANSWER: Nothing was done for many years, until the meeting of the Legislature in 1927 when a report was made known as the Jarman Report, which was authorized by the Legislature of 1925, on the feasibility of the resumption of hydraulic mining.

QUESTION: What did this report show?

ANSWER: This report (page 33) states that an "Inspection of the more important gravels in these districts for the present hydraulic mining commission showed that only 712,000,000 cubic yards could be regarded as workable under the changed conditions."

QUESTION: What was the result of this report?

ANSWER: This resulted in a bill being introduced in the Legislature known as the Cloudman Bill, asking for an appropriation of $300,000 to be expended by the State in acquiring dam sites with the idea that dams would be eventually constructed by the State and Federal Governments to restrain hydraulic mining debris and the State and Federal Governments to be reimbursed by the miners paying for storage of such debris behind those dams.

QUESTION: Did this bill become a law?

ANSWER: No, it was defeated in the Legislature, and two years later a similar bill for $200,000 was introduced, known as the Seawell Bill and this bill was passed by the Legislature but vetoed by the Governor.

QUESTION: What was the attitude of the California Debris Commission in regard to these bills?

ANSWER: When the first bill was introduced in the Legislature, and later defeated, a series of meetings were held before the mining section of the Commonwealth Club in San Francisco where both the Valley and the mining interests were given every facility to present arguments both pro and con and a great deal of information was disclosed. These meetings were attended by Colonel Thomas H. Jackson of the California Debris Commission who listened to all the arguments and later on, at the conclusion of the meetings he made a report to General Jadwin, Chief of Engineers of the U.S. Army, Washington, D.C. and in that report were some comments and conclusions which Colonel Jackson arrived at, as follows:

"The Board believes, therefore, that any resumption of hydraulic mining on a large scale should be undertaken only on such a basis as would justify private investors in assuming all the risks involved. This would mean that the mine owners should provide directly or indirectly all necessary debris-retention work.

"The Board concludes that the construction of retention dams with Federal funds to enable a resumption of hydraulic mining is not justified at the present time.

"The debris commission believes that the United States should not enter into partnership with a private power company for the purchase of storage rights."

QUESTION: Just what conclusion have the valley interests arrived at?

ANSWER: We maintain that the future prosperity and the extreme limit of this great State's development in the future depends upon its future water supply and not upon its gold product. Hydraulic mining, according to the Jarman report, could not last, under the most favorable conditions, much over twenty years; on the other hand it is vastly more important that the few reservoir sites in the mountains of the Sierra be retained for the storage of water for the development of power and for irrigation of the Sacramento and San Joaquin Valleys than it is to have these storage basins filled with mining debris and so lose that capacity for water storage for all time to come for irrigation and power purposes.

QUESTION: You have previously stated that at the time of the decision of Judge Sawyer in 1884, that at that time hydraulic mining was not proving very profitable. I presume because the richer gravel deposits had been pretty thoroughly worked out by that time. If such is the case, how would that condition be affected at the present time?

ANSWER: In the hearings before the Commonwealth Club, it was pretty well brought out that the cost of labor and material necessary for such mining operations is at least sixty-six and two-thirds per cent greater now than it was in the unrestricted mining days, and you must remember that the output of the enterprise (gold) has no higher value now than it had then. It would appear therefore that it would be quite uneconomical to carry on hydraulic mining now under conditions which might require more expensive methods to hold back the debris, than were ever used before.

QUESTION: About what is the average gross expected yield per cubic yard now in hydraulic mining?

ANSWER: For all practical purposes it has been considered a fair average yield per cubic yard in the middle and south Yuba mining region is 10 cents. In that section it has been shown that during the old hydraulic mining days the cost was $0.0453 for operations; if present advance costs today for labor, material, etc., are now sixty-six and two-thirds per cent more than the old cost, then today's cost would be $0.0755 and subtracting the latter figure from the estimated 10 cent gross, would leave a profit of $0.0245. In other words, if 1,000,000 cubic yards of material were washed away, the net profit would amount to $24,500 and if we take Jarman's report which contemplated washing of 137,392,000 cubic yards in the middle and south Yuba mining region in 20 years, this would average 6,869,600 yards a year. If that be done, the average net profit would be $168,305 and at eight per cent per annum, would represent an invested capital of $2,103,800.

I might also state that on the Yuba river three estimates were made on probable net returns, one by Mr. Jarman who got up the report to the State, the other by Mr. W. W. Waggoner, of Nevada City, representing mining interests and one by O. Von Geldern, representing Valley interests. Their conclusions were as follows:

Mr. Jarman: Gross receipts .109 less total expense .075 net returns .0340 per cubic yard.

Mr. Waggoner: Gross receipts .0981 less total expense .07 net return .0281 per cubic yard.

Mr. Von Geldern: Gross receipts .10 less total expense .0805 net return .0195 per cubic yard.

The average of the three above would be a net return of .0272 per cubic yard which would not appear very profitable as a mining proposition. Please remember that this is all on the Yuba River where the most valuable gravels are to be had. All the other rivers would not expect to show as good results as values in gravels are less.

QUESTION: Isn't there an old saying that there as been just as much money expended in the mountains in trying to get the gold out as there has been actually gold recovered?

ANSWER: Yes, there is such a saying and there is undoubtedly a great deal of truth in it. In any event, gold production is insignificant with agriculture, for example, the Jarman report estimates in 20 years behind three of the dams there MAY be produced $10,000,400 in gold; this would be an average of $500,000 per year. Now just compare this with the ANNUAL production of fruits, grapes, grain and other such products in the two small counties of Yuba and Sutter which average about $14,000,000 each year and requires vastly more labor than mining.

QUESTION: Were any estimates made on reservoir capacity for storage of mining debris and cost of the dams necessary for same?

ANSWER: Yes, in Colonel Jackson's report, the reservoir capacity which would be available behind nine dams on the Yuba, Bear and American Rivers would be 375,700,000 cubic yards of debris and these nine dams would cost about $12,085,600 and the average units cost for all of them for storage would therefore be $0.0286 per cubic yard, or practically three cents per cubic yard.

QUESTION: Would it not be vastly more beneficial to the whole state if in place of having the state and federal governments build these dams and have some 375 million cubic yds. of debris stored behind them in say the next 20 years, that this storage area be retained for the storage of water for the future needs of the state?

ANSWER: That question "hits the nail right on the head" and brings out our chief contention that it would be the height of folly for the State to go into partnership with a private industry, which, if it proved successful would mean that the State would reap no profit whatever, but on the other hand, would help in losing reservoir space for the storage of water for the future needs of the agricultural interests in the State. Colonel Jackson in his report particularly called attention to this matter in the case of the proposed dam at the Narrows on the Yuba River and behind which the capacity for storage for debris would be almost three times greater than the storage of any of the other eight dams; this dam would be the most expensive, the estimate being $3,524,000 and the storage was to be 117,000,000 cubic yards of debris; Colonel Jackson stated in connection with this proposed dam, "even though present plans may appear feasible to use this site for storage of debris without interference with its primary purpose of irrigation, this Commission feels that the project of which the site is an essential unit, is so vital to the welfare of the State as to preclude it from this investigation." This meant that it would conflict with the State's plan for the conservation of water.

QUESTION: Was there not some proposition offered by a power company in connection with this dam at the narrows?

ANSWER: Yes, the Yuba River Power Company made an offer that it would build this dam and sell outright for $1,500,000 some 350,000,000 cubic yards of storage space for debris. This dam had been planned as a commercial venture involving a combined power, irrigation and debris project and it was contemplated that the United States Government would furnish one-half the funds to purchase this storage and the State of California the other half, but Colonel Jackson in his report stated that "the Debris Commission believes that the United States should not enter into partnership with a private power company for the purchase of storage rights."

QUESTION: Is the water problem now serious in some portions of the state?

ANSWER: For centuries in the past the melting snows of the Sierra Nevadas filled the streams that poured into the Sacramento and San Joaquin Valleys and underneath the floor of the Valley millions of acre feet of water were stored. Rapid advances in agriculture made necessary the pumping of water from wells throughout these valleys and this has resulted in the lowering of that water table so that at present, in several of the counties of the San Joaquin Valley, the situation is getting alarming, and in the Sacramento Valley it would appear that in a few years a similar serious lowering of the water tables will occur. The first motor driven pump for irrigation was installed in Tulare County in 1901 and there was no water problem then, but records show that during the past four years, 400 wells have been abandoned in Tulare County and 1500 others have been deepened and their lifting capacity increased. Practically in 30 years this great underground reservoir in the San Joaquin has been largely dissipated and today the question is, whether or not surplus flood waters of the Sacramento River and its tributaries, now flowing into the ocean, can be diverted in the San Joaquin Valley to care for their increasing needs. According to Bulletin No. 12, Water Resources of California, compiled by the Department of Public Works, if all the water resources of the San Joaquin Valley were used, there "is little more than half enough water for its future needs." It would appear that before long, a very similar situation will prevail in the Sacramento Valley and that is why we seriously object to the construction of dams in the Sierras to hold mining debris in place of keeping that storage of water for future needs.

QUESTION: Well, this has all been very interesting and instructive. We do not know of any more questions to ask. Have you anything to suggest?

ANSWER: Yes, I would suggest that you consider all of these matters very carefully and seriously and that when you vote on this question next November, that you will come to the same conclusion that the Federal Government's Engineers have arrived at, that it would be unwise to enter into partnership with a private industry and that the State of California should not do so either. Also that you conclude that it is tremendously important to retain all possible storage basins for the storage of water for future development and needs of the State and that it would be the height of folly to sacrifice a large portion of that storage area for the storage of vast quantities of mining debris for the momentary gain of a few million dollars of gold in the next twenty years.

Hydraulic mining
Memories: My Seventy-Two Years in the Romantic County of Yuba, California by W. T. Ellis, Jr. Eugene: University of Oregon, 1939