Chapter 915 – Reading Glasses

As an abrasive, Lingao had Changhua quartz sand and local diatomaceous earth. The latter, properly sieved and graded, was currently serving as the abrasive for flat plate glass. But Lin Hanlong decided to use garnet abrasive anyway—in this timeline, garnet had been the standard optical lens grinding abrasive.

Lin Hanlong had his apprentice sieve the crushed powder first through a coarse sieve, then progressively through finer and finer meshes. The industrial sieves for abrasives were mostly brought from the old timeline; this timeline couldn't yet produce high-mesh industrial sieves. The final separated garnet powder became abrasive graded by particle size.

Meanwhile, Lin Hanlong set about making specialized machinery for optical processing. First, at the cost of one pack of five Nanhai Cigars, Chuqing Limited Edition, he bribed his colleague Sun Li from the machining workshop to work overtime making a steel "goblet"—technically called a spherical grinding dish. Its interior wall was a precisely lathed spherical surface whose radius had been calculated in advance. The steel goblet was a critical component of the spherical grinding machine, requiring high machining precision. Lin Hanlong didn't dare entrust it to a naturalized worker, so he specifically asked a transmigrator technician to handle it.

The spherical dish had to rotate on a flat surface. The drive system wasn't technically demanding; a mechanism like a bicycle would work. But connecting to the power shafting required advance application, and Lin Hanlong was too lazy to file a report. He simply went with a human-powered drive.

It took Lin Hanlong three weeks to fabricate and assemble all the spherical grinding machine's components. After finishing the processing machinery, he still needed fixtures to hold the glass precisely. This took him another three days. With everything ready, Lin Hanlong unstacked the glass cylinder into individual pieces, cleaned off the excess adhesive with alcohol-soaked cotton, then placed them on the iron plate to heat slowly. When the glass was warm, he applied sealing wax. The sealing wax slowly melted in the heat, forming a smooth surface on top of the glass. Lin Hanlong inspected it carefully, then turned down the furnace to let the iron plate cool.

The next step was much like ordinary machining. Fix the mold to the chuck on the swing arm, then lower the arm into the grinding dish. He and his apprentice took turns—one pedaling, one cranking. After more than an hour of this, the originally flat glass had been ground into a spherical surface. Lin Hanlong spent a long time measuring with a profile gauge. Satisfied that the spherical precision was acceptable, he removed the workpiece and declared they were done for the night.

This time, Lin Hanlong's tinkering attracted everyone's interest. Several people stayed to watch the glass-grinding process. The next morning, Zhong Lishi rushed out of his laboratory to find Lin Hanlong. First he examined the finished blanks and praised them, then asked, "After this is made, the first sample should be submitted to the Administrative Office for preservation, yes? Very significant commemoratively."

Lin Hanlong shook his head. "I just want to make a pair of reading glasses for someone to test."

"Who's farsighted?"

"A native. My apprentice's father. A fine craftsman—can't do precision work anymore because of farsightedness."

"Then why go to all this trouble? Just apply to the Planning Commission for a pair!"

"How many can there be? Farsightedness is extremely common among naturalized citizens. Demand is immense."

After the conversation, Lin Hanlong was officially assigned the task of developing optical lenses. Within two days, all eight raw pieces had been ground into blanks.

After rough grinding came fine grinding with finer abrasive. Lin Hanlong grew even more careful now. This went on for a week, until all eight blanks were fine-ground to the limits of profile-gauge measurement. Dr. Zhong came to observe again, this time bringing Zhan Wuya along. Zhan Wuya praised the product profusely but advised: It's just reading glasses—why such precision? Lin Hanlong replied that he was accumulating experience for making better optical instruments in the future.

After fine grinding, only polishing remained. But here, Lin Hanlong hit a snag. The polishing powder commonly used in the optical industry was extremely fine metal oxide particles. The metallurgy department said they could make iron oxide, but rendering it into powder was beyond them. Lin Hanlong had to send his iron oxide raw material to Xiao Bailang's facility for milling, but the output of sufficiently fine iron oxide was meager. In the end, he could only do the polishing by hand with coarse felt.

A few days later, Dr. Zhong came again. Lin Hanlong demonstrated an optical interference test, showing how his lenses were distorted compared to the reference. Zhong Lishi picked up a glass piece and focused light through it.

"Look how small this light spot is. I think you've done quite well."

"Precision still needs improvement. By optical industry standards—within a quarter wavelength."

Zhong Lishi nearly fell over. "This is the seventeenth century! Can this thing be used to make a telescope?"

"It would far exceed seventeenth-century standards."

"Then that's good enough. Let's present them to the Senate."

That very day, Lin Hanlong was appointed Chief Engineer for Optical Affairs. Establishing an optical factory was placed on the Executive Committee's agenda.

For Lin Hanlong, the most immediate change was the addition of an older skilled worker to the workshop—his apprentice's father, Cai Shengjie. The man was a skilled coppersmith who had lost his working capacity due to farsightedness. Now, with the reading glasses Lin Hanlong had made, he could return to frontline work.

It was past four in the afternoon at the Bairren Industrial District. After the Chengmai victory, the rifle-bearing Fuboian soldiers who'd previously patrolled had disappeared. Now it was "Worker Patrol Teams" carrying clubs with "Patrol" armbands.

Three men emerged from a street corner, striding toward the factory district gate. In the lead was Lin Hanlong, wearing a camouflage tank top with a bulging black canvas bag slung over his shoulder. Behind him trailed one old, one young, both in blue work clothes.

Inside the industrial district, a rail system transported workers. Steam locomotives pulled open freight cars. Whistles sounded from all directions. From high loudspeakers came music and broadcasts—an industrial symphony, chaotic yet vibrant.

After getting off at the Science and Technology Department stop, Lin Hanlong walked to the workshop bearing the signboard "Science and Technology Department, Optical Testing Plant." There weren't many people in the workshop. Walking in, he noticed the gas lamp valves had been properly shut off—good, safety education was working.