one may contend that its registration is compulsory. However, Section 59 of the Transfer of Property Act mandates that every mortgage other than a mortgage by deposit of title deeds can be effected only by a registered instrument. In the face of it, in our opinion, when the debtor deposits with the creditor title deeds of the property for the purpose of security, it becomes a mortgage in terms of Section 58(f) of the Transfer of Property Act and no registered instrument is required under Section 59 thereof as in other classes of mortgage. The essence of a mortgage by deposit of title deeds is the handing over, by a borrower to the creditor, the title deeds of immovable property with the intention that those documents shall constitute security, enabling the creditor to recover the money lent. After the deposit of the title deeds the creditor and borrower may record the transaction in a memorandum but such a memorandum would not be an instrument of mortgage. A memorandum reducing other