From Arthur Donaldson
Philadelphia Octr the 1st 1785
I Esteem my Self highly honourd by your Excelencys faivour to Mr Hollingsworth1 and Shall Imbrace the Opertunity of Serving you with the greatest freedom Theirfore in the first place hope to remove your doubts of the Hippopomos being Applicable to your purpose by Viewing the Inclosd draught & discription which was publishd in the Pennsylvania Magazine for May 17752 but on Account of the War was not put into practice untill this Sumer having the Small Alteration of bringing the hoisting rope Over the horses back & Inverting the Capston. My Maner of useing this Machine is by having Severall large lighters to Carry off the mud &c. to the most Convenient place whilst the Machine is fully Imployd in raiseing it Another Methood may probably be more Convenient for your purpose I would recomend a Vesell about 50 ft long 20 ft broad & about 4 ft deep So as to load the mud in the Same vesell that has the machine in lett hir be Intirely flatt at botom She will lay Stedy on the water & Contain 40 or 50 Cart loads & not Exceed the draught of 3 ft water when loaded She may be dischargd Again by the Griples the Contents thrown in to wagons or on a Shore that is Convenient with A border of a wharf when it may be too Soft to Shovel with Conveniency their it can lay a few days to dry hard enough to move with more ease this will Save a consider expence in equiping & working difrent vesells as well as Shoveling &c. but is not applicable here as Such a Vesell Could not work in many docks whare most wanted & other reasons which may not accur with you In adopting this alteration it will be necessary to Consider the Situation of your ground & Safety of harbour if your Shore is Clear of Stones the botom near levell it will be the better but will require a Safe harbour in rough weather twoo or three men with a horse may load this vesell in a few howers & by takeing advantage of the tide Come on Shore whare She may Ground safely untill dischargd as above I flatter my Self this mode will be Equell to your Excellencys wish and will not add above one third to the Expence of the within discribed vesell but in Case more dispatch is required then this mode will Admitt of you Can adopt the difrent Vesells in Either Case the Expence of Machinery will be much the Same the whole of which will add about one hundred pound to the price of the vesell & horse to work with.
If After this Information youl think proper to go into the buisness by Either methood and will honour me with your directions3 I Shall proceed Accordingly if you wish to have a Good workman Sent to Conduct the building a Sutable vesell Shall endeavour to procure one to whome I Can give particular directions it may be best to gett the Prin[c]iple Ironwork don here by the hand that did mine whoes Experience may be Improv’d and on whome I Can readily Attend & when ready have them Conveyd round by wa⟨ter⟩ If you wish to hurrey the work (as I Conceive the winter frost us⟨e⟩full to pulverize the manure) I Shall make free to recomend the procureing 1500 or 2000 ft of 2 & ½ Inch Oake plank & the Same Quantity of 2 In. d[itt]o which may probably require time the other Stuff can undoubtedly be got on Short notice Such as the large Vesell would Cost about £300 in this place but Expect your plenty of timber will greatly reduce the price as to the other methood you Can be better informd the Cost of lighters by your neighbours If you wish to Imploy a Carpenter in your neighbour hood to direct the building I will Send you a Sutable Draught or modell for him to work by if required of Either Sort you Chuse—In Case you proceed I will do my Self the pleasure of an Excurtion into your neighbourhood a few weeks to See the works put together when prepared for beliv⟨e⟩ me Sir it will give me great pleasure to have it in my power to Convay Any usefull Information to mankind More Especially in So usefull an Obiect as the reinstating the firtilety of so valuable a part of your first Setlements under the patronage of the first Charactor to whome the united States are Indebted theirfore heartily desire your Excelency to use the freedom of nameing Any thing I have in my power to Serve you in without entertaneing the Idea of trouble to me I will not for the present tire your patience with more particulars but to Inquire if you think to Imploy the griples in any thing but Soft Mud as difrent Shapes are necessary for difrent purposes I have twoo pair one without teeth for Soft Mudd and Sand (which I raise for morter) the others have Circular lips with Strong teeth for hard dirt gravell Stones &c. the former supose to be most Sutable for your purpose. I have the honour to be with submition your Excelencys Most Obligd H. Sert
2. Donaldson enclosed from the May 1775 Pennsylvania Magazine: or, American Monthly Museum, the full-page engraving of his dredge (1:206) and the “Description of the Engine” (1:207–8). The artist Pierre-Eugène du Simitière recorded in his notebook in 1775 having made “—a drawing in India ink of a machine for cleansing docks & harbour done for arthur donaldson the Inventor[,] for the Pennsylvania magazine” (William John Potts, “Du Simitiere, Artist, Antiquary, and Naturalist, Projector of the First American Museum, with Some Extracts from His Notebook,” Pennsylvania Magazine of History and Biography, 13 , 341–75).