Conservation concept states that "an accountant shouldn't anticipate profit, but must provide for all losses". The concept that an accountant shouldn't anticipate profit, but must provide for all losses is known as The conservatism concept.
Patents accounts are Real account. Patent right is classified as intangible asset and appear on balance sheet, that is why it is of nature of real account. The balances of real accounts are not cancelled out at the end of an accounting period but are carried over to the next period.
Reserve capital means Part of subscribed uncalled capital. Reserve Capital is defined as a part of subscribed uncalled capital, which will not be called up until and unless the company goes into liquidation.
Revenue from sale of product ordinarily is reported as part of earning in the period