1. The bridge over the Daugava. 2. Follow their example! 3. Electret. 4. Accuracy is guaranteed!
1. Construction of a bridge over the Daugava River by a new method in Riga.
All parts are made on the river bank.
The process of bridge construction.
2. The work of a textile factory.
Production of fabrics on weaving machines.
Machines that process the sharpening of parts.
3. The study of electretes in experimental laboratories.
The use of electretes in photo labs.
The photo lab is in operation.
Electronic photos.
4. VDNH. Experiments with a new device for watch factories.
Key words
Bridge, Riga, textile factory, electret, photo labs, device for watch factories