Explain the following article:

1493(own explanation and example)

• Effect of loss of things at the time of sale
• When a thing considered lost

1494(own explanation and example)

• Effect of loss in case of specific goods

1495(own explanation and example)

• Principal obligation of the vendor
• Obligation to transfe ownership and to deliver
• Obligations to take care of, and preserve, the thing

1496(own explanation and example)

• Transfer of ownership and to deliver
• Ways of effecting constructive delivery