they spread....

जले तैलं खले गुह्यं पात्रे दानं मनागपि। 

प्राज्ञे शास्त्रम् स्वयम् याति विस्तारे वस्तुशक्तितः॥

चाणक्याद्

jale tailaṁ khale guhyaṁ pātre dānaṁ manāgapi| 

prājñe śāstram svayam yāti vistāre vastuśaktitaḥ||

cāṇakyād

Another sweet gem from Chanakya

Oil added to water 

Secret shared with an idiot or an evil minded fellow

Gift given to a deserving and nice person

Knowledge of science imparted to a man with great intellect

These spread and multiply all by themselves especially because of the qualities of the recepients..
even if the quantity supplied is very small.

Oil and water do not mix with one another.. They have different specific gravities too..Obviously oil added to water floats over a vast area over the surface.

When we disclose a secret to an idiot or an indiscreet person, we know what happens.. The matter will be given a lot of make up too and presented everywhere ..

When a gift is given to a nice and deserving person, he will be grateul and we gain a good friend for ever.. The gift would be used for noble purposes..

And when we teach a nice, earnest and briilliant student, the knowledge and the benefits arising out of it grow and spread millionfold..

Of course special mention is to be made of secrets shared with idiots..