From available data, combined with information picked up from examination of such remains of the shells as were recovered, the experts decided that the projectile was seven feet in length with an external diameter of four inches; that the weapon was a 120-calibre gun, with a muzzle velocity of from 3000 to 3500 feet per second and with an extreme range of fifty-five miles.
It was also established that at a range of twenty-five miles—the distance between the position of the submarine and the town of Portsmouth—the projectiles must have attained the extreme vertical height of eight and a half miles.
In the midst of his labours, Brian Strong was called to the telephone in the Commodore's office to answer an urgent inquiry from the Admiralty.
Sir John Pilrig was at the instrument, anxiously inquiring whether Mr. Strong could give him any information about the Rioguayan submarines.
"I cannot," replied Brian bluntly. He was not the sort of man to beat about the bush and try to give the impression that he was in the position to supply the information. "Aircraft was my line. But my nephew here can give you particulars."
Peter took his uncle's place at the telephone and described the submarines he had seen manoeuvring off San Antonio.
"They were possibly instructional craft," he added. "Somewhat resembling our obsolete C class."
He proceeded to describe the craft in clear technical language, which compelled Sir John to inquire in what circumstances he had gained the knowledge.
"I was a sub-lieutenant, R.N., sir," he replied. "Retired under the regulations for the reduction of personnel."
"Ah," commented the Deputy Chief of Staff. "Very good. I'll ring off now."