Special to The New York Times.

HAVANA, April 16--The days of Fidel Castro, rebel leader who has been fighting the troops of President Fulgencio Batista in Oriente province since Dec. 2, 1956, are numbered according to informed sources.

It is believed that the Castro force's supply of arms and ammunition is being rapidly depleted, while the Cuban Army is equipped with the most men weapons and the troops number up to 30,000.

Reports from Oriente Province indicate that Senor Castro is losing men and arms daily.  He had a maximum of about 2,000 men.  The death toll of young revolutionists in Oriente and in towns and villages all over the island is said to be fifteen to twenty daily.

The money poured into the rebel cause has reached a high figure.  The total value of the arms that have been seized by President Batista in Cuba and by the United States Government in teh United States from the revolutionists and their supporters is not available.  However, the amount runs into many millions of dollars.

These millions have been provided by individuals in exile in the United States and elsewhere, by a few well-known business men in Cuba, and by the general public, who have purchased hundreds of thousands of dollars' worth of rebel bonds.

A submachine gun that costs $250 when purchased legally can cost twice or three times that amount when bought clandestinely on the black market.  To this must be added the cost of keeping these weapons in hiding in the United States--where most of them have been bought--the hiring of guards and purchase of influence, the buying of ships to move the arms to Cuba, the paying of the high salaries demanded by the crews, of meeting the cost of landing the arms.

Only two days ago an arms shipment that arrived in western Cuba aboard a small vessel fell into the Government's hands.  It had cost the rebels many thousands of dollars.

Added to all this is a lack of coordination and planning among the different groups of Cubans, in Cuba and abroad, who are fighting the Batista regime.

Some of the revolutionists are much disillusioned over teh failure of the general revolutionary strike that was to have begun a week ago.  Its failure is attributed by overseers to lack of coordination among the revolutionists, swift action o military authorities and the fact that neither labor nor the general public supported the movement.

On March 13, 1957, youthful revolutionists in Havana tried to assassinate President Batista in an assault in broad daylight on the Presidential Palace.  It failed and all forty attackers who penetrated the palace were killed.

Efforts to turn the armed forces against the regime have failed--in part, no doubt, because President Batista is himself a military man who came up from teh ranks and has given the armed forces virtually everything the national economy can afford.

From all these factors it appears now that armed revolution against Batista has little chance of success.  The probability, in the opinion of qualified observers, is that President Batista will be able to hold the general elections scheduled now for Nov. 3.

But there seems no doubt, also, that Senor Castro and his insurgents will go on fighting.

An attempt by Castro insurgents today to destroy or damage the Yateritas Aqueduct, which furnishes water to the United States Naval Base at Guantanamo, in Oriente Province, was defeated, according to a late communiqué from Camp Columbia Army Headquarters here.  Two rebels were killed in the encounter with troops defending the aqueduct, headquarters said.

In the town of Guantanamo, which is several miles from the United States base, one policeman was wounded when a group of rebels fired on the residence of Mayor Franco.  An army unit drove the rebel group into a near-by wooden section.

Two rebels were killed and several wounded near Niquero on teh south coast of Oriente Province in clashes with Government troops, headquarters said.

In Havana the police reported they had killed two revolutionists on the Rancho Boyeros Highway leading to the Jose Marti International Airport.

The rector of the Sacred Heart School in Sagua La Granda, in Las Villas Province, which rebels held in tow days of fighting last week, has sent a message of appreciation to Col. Angel Garcia, chief of the military province of Las Villas, praising the action of the armed forces, Camp Columbia said.

Capt. Antonio Sanson of Havana, co-pilot of a Cubana Airlines plane who is seeking asylum in the United States, was questioned for several hours yesterday at the United States Immigration and Naturalization Service, 70 Columbus Avenue.  Sol Marks, deputy district director of the service, said the hearing was the institution of deportation proceedings against the flier.

The Cuban, who says he fears to return to Cuban because of his anit-Batista views, was ordered to appear before a special inquiry section of the Immigration Service next Wednesday to show cause why he should not be deported.

Captain Sanson stepped out of a Cubana Airlines plane at Idlewild on Tuesday shortly before the scheduled departure of the plane for Havana.

The captain's wife, a daughter, 15 years old, and a son, 11, are now in Cuba.  If he is permitted to remain in this country, Captain Sanson said he would go to Miami and try to have his family join him there.