Another early form of marine engine was that in which the side levers were arranged as levers of the third order, the fulcrum being at one end and the steam cylinder placed between it and the connecting-rod. The peculiar motion thereby given to the machinery caused this type to be known as the grasshopper engine, from a fancied resemblance to the long legs of a grasshopper. The direct-acting engines were much more compact, more powerful, and lighter than the old side levers. The necessity of providing a connecting-rod of sufficient length was met by Messrs. Maudslay by the provision of two cylinders. The cross-head was not unlike the letter =[T]=, the foot of which passed down between the cylinders, and the lower end of this was fitted with a journal from which the connecting-rod extended to the crank in the axle. A still further improvement was made when the oscillating engines were invented, which form an even more compact and simple type. Messrs. Maudslay fitted a pair of oscillating engines in 1828 into the paddle-steamer _Endeavour_, and subsequently into several ships. This form of engine was improved upon by Mr. John Penn, the famous engineer at Blackwall, and the perfection which he gave it has not been surpassed. The great feature of this method is that the trunnions are hollow, and the steam is admitted to and exhausted from the cylinders through them. The connecting-rod is dispensed with and the upper end of the piston-rod acts directly on the crank pin. This type of engine is the most economical for space and weight that has yet been provided for paddle-wheel engines, the majority of which of late years have been made on this system. Its adaptability for certain classes of work has given the paddle-wheel a long lease of life. Paddles are peculiarly suitable for certain conditions, such as smooth waters and shallow rivers, where speed and light draught combined with considerable carrying power are essential. The Indian rivers, for instance, early demanded suitable steamers, and the paddle-steamers _Lord W. Bentinck_, _Thames_, _Megna_, and _Jumna_ were built of iron in 1832 for the East India Company for the navigation of the Ganges. They were designed and constructed by Maudslay, Sons, and Field, and fitted with oscillating cylinder engines of 30 nominal horse-power. They were flat-bottomed and were shipped to India in pieces. They were 120 feet in length, 22 feet beam, and had a draught of 2 feet. Their tonnage was 275, builders’ measurement. The steamers sent to India, however, from over sea were not the only ones in that country.